[PATCH 2.6.27.y 00/11] *** SUBJECT HERE ***

[PATCH 2.6.27.y 00/11] *** SUBJECT HERE ***

[Theodore Ts'o]

These are the patches backported by Jayson R. King.  I've eyeballed
them, and run them through a xfsqa test run, and they look good to me.

Greg, please apply them to the 2.6.27 kernel.

      	     	   					- Ted

Aneesh Kumar K.V (10):
  ext4: invalidate pages if delalloc block allocation fails.
  ext4: Make sure all the block allocation paths reserve blocks
  ext4: Add percpu dirty block accounting.
  ext4: Retry block reservation
  ext4: Retry block allocation if we have free blocks left
  ext4: Use tag dirty lookup during mpage_da_submit_io
  vfs: Remove the range_cont writeback mode.
  vfs: Add no_nrwrite_index_update writeback control flag
  ext4: Fix file fragmentation during large file write.
  ext4: Implement range_cyclic in ext4_da_writepages instead of
    write_cache_pages

Mingming Cao (1):
  percpu counter: clean up percpu_counter_sum_and_set()

 fs/ext4/balloc.c               |   88 +++++++++---
 fs/ext4/ext4.h                 |   13 ++
 fs/ext4/ext4_sb.h              |    1 +
 fs/ext4/inode.c                |  314 ++++++++++++++++++++++++++++------------
 fs/ext4/mballoc.c              |   39 +++--
 fs/ext4/super.c                |    8 +-
 include/linux/percpu_counter.h |   12 +-
 include/linux/writeback.h      |   10 +-
 lib/percpu_counter.c           |    8 +-
 mm/page-writeback.c            |   16 +-
 10 files changed, 360 insertions(+), 149 deletions(-)

[PATCH 2.6.27.y 01/11] ext4: invalidate pages if delalloc block allocation fails.

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit c4a0c46ec92c194c873232b88debce4e1a448483 upstream.

We are a bit agressive in invalidating all the pages. But
it is ok because we really don't know why the block allocation
failed and it is better to come of the writeback path
so that user can look for more info.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/inode.c |   85 +++++++++++++++++++++++++++++++++++++++++++++++--------
 1 files changed, 73 insertions(+), 12 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index aeebfc2..ebd83cd 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1821,6 +1821,39 @@ static inline void __unmap_underlying_blocks(struct inode *inode,
 		unmap_underlying_metadata(bdev, bh->b_blocknr + i);
 }
 
+static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
+					sector_t logical, long blk_cnt)
+{
+	int nr_pages, i;
+	pgoff_t index, end;
+	struct pagevec pvec;
+	struct inode *inode = mpd->inode;
+	struct address_space *mapping = inode->i_mapping;
+
+	index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
+	end   = (logical + blk_cnt - 1) >>
+				(PAGE_CACHE_SHIFT - inode->i_blkbits);
+	while (index <= end) {
+		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+		if (nr_pages == 0)
+			break;
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+			index = page->index;
+			if (index > end)
+				break;
+			index++;
+
+			BUG_ON(!PageLocked(page));
+			BUG_ON(PageWriteback(page));
+			block_invalidatepage(page, 0);
+			ClearPageUptodate(page);
+			unlock_page(page);
+		}
+	}
+	return;
+}
+
 /*
  * mpage_da_map_blocks - go through given space
  *
@@ -1830,7 +1863,7 @@ static inline void __unmap_underlying_blocks(struct inode *inode,
  * The function skips space we know is already mapped to disk blocks.
  *
  */
-static void mpage_da_map_blocks(struct mpage_da_data *mpd)
+static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 {
 	int err = 0;
 	struct buffer_head *lbh = &mpd->lbh;
@@ -1841,7 +1874,7 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
 	 * We consider only non-mapped and non-allocated blocks
 	 */
 	if (buffer_mapped(lbh) && !buffer_delay(lbh))
-		return;
+		return 0;
 
 	new.b_state = lbh->b_state;
 	new.b_blocknr = 0;
@@ -1852,10 +1885,38 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
 	 * to write simply return
 	 */
 	if (!new.b_size)
-		return;
+		return 0;
 	err = mpd->get_block(mpd->inode, next, &new, 1);
-	if (err)
-		return;
+	if (err) {
+
+		/* If get block returns with error
+		 * we simply return. Later writepage
+		 * will redirty the page and writepages
+		 * will find the dirty page again
+		 */
+		if (err == -EAGAIN)
+			return 0;
+		/*
+		 * get block failure will cause us
+		 * to loop in writepages. Because
+		 * a_ops->writepage won't be able to
+		 * make progress. The page will be redirtied
+		 * by writepage and writepages will again
+		 * try to write the same.
+		 */
+		printk(KERN_EMERG "%s block allocation failed for inode %lu "
+				  "at logical offset %llu with max blocks "
+				  "%zd with error %d\n",
+				  __func__, mpd->inode->i_ino,
+				  (unsigned long long)next,
+				  lbh->b_size >> mpd->inode->i_blkbits, err);
+		printk(KERN_EMERG "This should not happen.!! "
+					"Data will be lost\n");
+		/* invlaidate all the pages */
+		ext4_da_block_invalidatepages(mpd, next,
+				lbh->b_size >> mpd->inode->i_blkbits);
+		return err;
+	}
 	BUG_ON(new.b_size == 0);
 
 	if (buffer_new(&new))
@@ -1868,7 +1929,7 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
 	if (buffer_delay(lbh) || buffer_unwritten(lbh))
 		mpage_put_bnr_to_bhs(mpd, next, &new);
 
-	return;
+	return 0;
 }
 
 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
@@ -1937,8 +1998,8 @@ flush_it:
 	 * We couldn't merge the block to our extent, so we
 	 * need to flush current  extent and start new one
 	 */
-	mpage_da_map_blocks(mpd);
-	mpage_da_submit_io(mpd);
+	if (mpage_da_map_blocks(mpd) == 0)
+		mpage_da_submit_io(mpd);
 	mpd->io_done = 1;
 	return;
 }
@@ -1980,8 +2041,8 @@ static int __mpage_da_writepage(struct page *page,
 		 * and start IO on them using writepage()
 		 */
 		if (mpd->next_page != mpd->first_page) {
-			mpage_da_map_blocks(mpd);
-			mpage_da_submit_io(mpd);
+			if (mpage_da_map_blocks(mpd) == 0)
+				mpage_da_submit_io(mpd);
 			/*
 			 * skip rest of the page in the page_vec
 			 */
@@ -2102,8 +2163,8 @@ static int mpage_da_writepages(struct address_space *mapping,
 	 * Handle last extent of pages
 	 */
 	if (!mpd.io_done && mpd.next_page != mpd.first_page) {
-		mpage_da_map_blocks(&mpd);
-		mpage_da_submit_io(&mpd);
+		if (mpage_da_map_blocks(&mpd) == 0)
+			mpage_da_submit_io(&mpd);
 	}
 
 	wbc->nr_to_write = to_write - mpd.pages_written;
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 02/11] percpu counter: clean up percpu_counter_sum_and_set()

[Theodore Ts'o]

From: Mingming Cao <cmm@us.ibm.com>

commit 1f7c14c62ce63805f9574664a6c6de3633d4a354 upstream.

percpu_counter_sum_and_set() and percpu_counter_sum() is the same except
the former updates the global counter after accounting.  Since we are
taking the fbc->lock to calculate the precise value of the counter in
percpu_counter_sum() anyway, it should simply set fbc->count too, as the
percpu_counter_sum_and_set() does.

This patch merges these two interfaces into one.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/balloc.c               |    2 +-
 include/linux/percpu_counter.h |   12 +++---------
 lib/percpu_counter.c           |    8 +++-----
 3 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 8b7c776..344ec1c 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1778,7 +1778,7 @@ ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
 #ifdef CONFIG_SMP
 	if (free_blocks - root_blocks < FBC_BATCH)
 		free_blocks =
-			percpu_counter_sum_and_set(&sbi->s_freeblocks_counter);
+			percpu_counter_sum(&sbi->s_freeblocks_counter);
 #endif
 	if (free_blocks <= root_blocks)
 		/* we don't have free space */
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 2083888..9007ccd 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -35,7 +35,7 @@ int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount);
 void percpu_counter_destroy(struct percpu_counter *fbc);
 void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
-s64 __percpu_counter_sum(struct percpu_counter *fbc, int set);
+s64 __percpu_counter_sum(struct percpu_counter *fbc);
 
 static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 {
@@ -44,19 +44,13 @@ static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 
 static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
 {
-	s64 ret = __percpu_counter_sum(fbc, 0);
+	s64 ret = __percpu_counter_sum(fbc);
 	return ret < 0 ? 0 : ret;
 }
 
-static inline s64 percpu_counter_sum_and_set(struct percpu_counter *fbc)
-{
-	return __percpu_counter_sum(fbc, 1);
-}
-
-
 static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
 {
-	return __percpu_counter_sum(fbc, 0);
+	return __percpu_counter_sum(fbc);
 }
 
 static inline s64 percpu_counter_read(struct percpu_counter *fbc)
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 4a8ba4b..a866389 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -52,7 +52,7 @@ EXPORT_SYMBOL(__percpu_counter_add);
  * Add up all the per-cpu counts, return the result.  This is a more accurate
  * but much slower version of percpu_counter_read_positive()
  */
-s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
+s64 __percpu_counter_sum(struct percpu_counter *fbc)
 {
 	s64 ret;
 	int cpu;
@@ -62,11 +62,9 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
 	for_each_online_cpu(cpu) {
 		s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
 		ret += *pcount;
-		if (set)
-			*pcount = 0;
+		*pcount = 0;
 	}
-	if (set)
-		fbc->count = ret;
+	fbc->count = ret;
 
 	spin_unlock(&fbc->lock);
 	return ret;
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 03/11] ext4: Make sure all the block allocation paths reserve blocks

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit a30d542a0035b886ffaafd0057ced0a2b28c3a4f upstream.

With delayed allocation we need to make sure block are reserved before
we attempt to allocate them. Otherwise we get block allocation failure
(ENOSPC) during writepages which cannot be handled. This would mean
silent data loss (We do a printk stating data will be lost). This patch
updates the DIO and fallocate code path to do block reservation before
block allocation. This is needed to make sure parallel DIO and fallocate
request doesn't take block out of delayed reserve space.

When free blocks count go below a threshold we switch to a slow patch
which looks at other CPU's accumulated percpu counter values.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/balloc.c  |   58 ++++++++++++++++++++++++++++++++++++++--------------
 fs/ext4/ext4.h    |   13 +++++++++++
 fs/ext4/inode.c   |    5 +---
 fs/ext4/mballoc.c |   23 +++++++++++---------
 4 files changed, 69 insertions(+), 30 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 344ec1c..1c0edd8 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1754,6 +1754,32 @@ out:
 	return ret;
 }
 
+int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
+						ext4_fsblk_t nblocks)
+{
+	s64 free_blocks;
+	ext4_fsblk_t root_blocks = 0;
+	struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+
+	free_blocks = percpu_counter_read(fbc);
+
+	if (!capable(CAP_SYS_RESOURCE) &&
+		sbi->s_resuid != current->fsuid &&
+		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
+		root_blocks = ext4_r_blocks_count(sbi->s_es);
+
+	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
+		free_blocks = percpu_counter_sum(&sbi->s_freeblocks_counter);
+
+	if (free_blocks < (root_blocks + nblocks))
+		/* we don't have free space */
+		return -ENOSPC;
+
+	/* reduce fs free blocks counter */
+	percpu_counter_sub(fbc, nblocks);
+	return 0;
+}
+
 /**
  * ext4_has_free_blocks()
  * @sbi:	in-core super block structure.
@@ -1775,18 +1801,17 @@ ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
 		sbi->s_resuid != current->fsuid &&
 		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
 		root_blocks = ext4_r_blocks_count(sbi->s_es);
-#ifdef CONFIG_SMP
-	if (free_blocks - root_blocks < FBC_BATCH)
-		free_blocks =
-			percpu_counter_sum(&sbi->s_freeblocks_counter);
-#endif
+
+	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
+		free_blocks = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
+
 	if (free_blocks <= root_blocks)
 		/* we don't have free space */
 		return 0;
 	if (free_blocks - root_blocks < nblocks)
 		return free_blocks - root_blocks;
 	return nblocks;
- }
+}
 
 
 /**
@@ -1865,14 +1890,11 @@ ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		*count = ext4_has_free_blocks(sbi, *count);
-	}
-	if (*count == 0) {
-		*errp = -ENOSPC;
-		return 0;	/*return with ENOSPC error */
+		if (ext4_claim_free_blocks(sbi, *count)) {
+			*errp = -ENOSPC;
+			return 0;	/*return with ENOSPC error */
+		}
 	}
-	num = *count;
-
 	/*
 	 * Check quota for allocation of this block.
 	 */
@@ -2067,9 +2089,13 @@ allocated:
 	le16_add_cpu(&gdp->bg_free_blocks_count, -num);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
-	if (!EXT4_I(inode)->i_delalloc_reserved_flag)
-		percpu_counter_sub(&sbi->s_freeblocks_counter, num);
-
+	if (!EXT4_I(inode)->i_delalloc_reserved_flag && (*count != num)) {
+		/*
+		 * we allocated less blocks than we
+		 * claimed. Add the difference back.
+		 */
+		percpu_counter_add(&sbi->s_freeblocks_counter, *count - num);
+	}
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
 		spin_lock(sb_bgl_lock(sbi, flex_group));
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1985721..7b666b2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1015,6 +1015,8 @@ extern ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
 					unsigned long *count, int *errp);
 extern ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t goal, unsigned long *count, int *errp);
+extern int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
+						ext4_fsblk_t nblocks);
 extern ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
 						ext4_fsblk_t nblocks);
 extern void ext4_free_blocks (handle_t *handle, struct inode *inode,
@@ -1245,6 +1247,17 @@ do {								\
 		__ext4_std_error((sb), __func__, (errno));	\
 } while (0)
 
+#ifdef CONFIG_SMP
+/* Each CPU can accumulate FBC_BATCH blocks in their local
+ * counters. So we need to make sure we have free blocks more
+ * than FBC_BATCH  * nr_cpu_ids. Also add a window of 4 times.
+ */
+#define EXT4_FREEBLOCKS_WATERMARK (4 * (FBC_BATCH * nr_cpu_ids))
+#else
+#define EXT4_FREEBLOCKS_WATERMARK 0
+#endif
+
+
 /*
  * Inodes and files operations
  */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ebd83cd..7a1d2e5 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1564,13 +1564,10 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
 	md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
 	total = md_needed + nrblocks;
 
-	if (ext4_has_free_blocks(sbi, total) < total) {
+	if (ext4_claim_free_blocks(sbi, total)) {
 		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 		return -ENOSPC;
 	}
-	/* reduce fs free blocks counter */
-	percpu_counter_sub(&sbi->s_freeblocks_counter, total);
-
 	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
 	EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
 
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index c7dc115..d9bff44 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3194,9 +3194,15 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 	 * at write_begin() time for delayed allocation
 	 * do not double accounting
 	 */
-	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
-		percpu_counter_sub(&sbi->s_freeblocks_counter,
-					ac->ac_b_ex.fe_len);
+	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED) &&
+			ac->ac_o_ex.fe_len != ac->ac_b_ex.fe_len) {
+		/*
+		 * we allocated less blocks than we calimed
+		 * Add the difference back
+		 */
+		percpu_counter_add(&sbi->s_freeblocks_counter,
+				ac->ac_o_ex.fe_len - ac->ac_b_ex.fe_len);
+	}
 
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi,
@@ -4649,14 +4655,11 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		ar->len = ext4_has_free_blocks(sbi, ar->len);
-	}
-
-	if (ar->len == 0) {
-		*errp = -ENOSPC;
-		return 0;
+		if (ext4_claim_free_blocks(sbi, ar->len)) {
+			*errp = -ENOSPC;
+			return 0;
+		}
 	}

[PATCH 2.6.27.y 04/11] ext4: Add percpu dirty block accounting.

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 6bc6e63fcd7dac9e633ea29f1fddd9580ab28f3f upstream.

This patch adds dirty block accounting using percpu_counters.  Delayed
allocation block reservation is now done by updating dirty block
counter.  In a later patch we switch to non delalloc mode if the
filesystem free blocks is greater than 150% of total filesystem dirty
blocks

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao<cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/balloc.c  |   62 ++++++++++++++++++++++++++++++++++------------------
 fs/ext4/ext4_sb.h |    1 +
 fs/ext4/inode.c   |   22 +++++++++---------
 fs/ext4/mballoc.c |   31 ++++++++++++--------------
 fs/ext4/super.c   |    8 ++++++-
 5 files changed, 73 insertions(+), 51 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 1c0edd8..6b6b560 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1757,26 +1757,38 @@ out:
 int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
 						ext4_fsblk_t nblocks)
 {
-	s64 free_blocks;
+	s64 free_blocks, dirty_blocks;
 	ext4_fsblk_t root_blocks = 0;
 	struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+	struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
 
-	free_blocks = percpu_counter_read(fbc);
+	free_blocks  = percpu_counter_read_positive(fbc);
+	dirty_blocks = percpu_counter_read_positive(dbc);
 
 	if (!capable(CAP_SYS_RESOURCE) &&
 		sbi->s_resuid != current->fsuid &&
 		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
 		root_blocks = ext4_r_blocks_count(sbi->s_es);
 
-	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
-		free_blocks = percpu_counter_sum(&sbi->s_freeblocks_counter);
-
-	if (free_blocks < (root_blocks + nblocks))
+	if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
+						EXT4_FREEBLOCKS_WATERMARK) {
+		free_blocks  = percpu_counter_sum(fbc);
+		dirty_blocks = percpu_counter_sum(dbc);
+		if (dirty_blocks < 0) {
+			printk(KERN_CRIT "Dirty block accounting "
+					"went wrong %lld\n",
+					dirty_blocks);
+		}
+	}
+	/* Check whether we have space after
+	 * accounting for current dirty blocks
+	 */
+	if (free_blocks < ((s64)(root_blocks + nblocks) + dirty_blocks))
 		/* we don't have free space */
 		return -ENOSPC;
 
-	/* reduce fs free blocks counter */
-	percpu_counter_sub(fbc, nblocks);
+	/* Add the blocks to nblocks */
+	percpu_counter_add(dbc, nblocks);
 	return 0;
 }
 
@@ -1792,23 +1804,28 @@ int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
 ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
 						ext4_fsblk_t nblocks)
 {
-	ext4_fsblk_t free_blocks;
+	ext4_fsblk_t free_blocks, dirty_blocks;
 	ext4_fsblk_t root_blocks = 0;
+	struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+	struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
 
-	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+	free_blocks  = percpu_counter_read_positive(fbc);
+	dirty_blocks = percpu_counter_read_positive(dbc);
 
 	if (!capable(CAP_SYS_RESOURCE) &&
 		sbi->s_resuid != current->fsuid &&
 		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
 		root_blocks = ext4_r_blocks_count(sbi->s_es);
 
-	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
-		free_blocks = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
-
-	if (free_blocks <= root_blocks)
+	if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
+						EXT4_FREEBLOCKS_WATERMARK) {
+		free_blocks  = percpu_counter_sum_positive(fbc);
+		dirty_blocks = percpu_counter_sum_positive(dbc);
+	}
+	if (free_blocks <= (root_blocks + dirty_blocks))
 		/* we don't have free space */
 		return 0;
-	if (free_blocks - root_blocks < nblocks)
+	if (free_blocks - (root_blocks + dirty_blocks) < nblocks)
 		return free_blocks - root_blocks;
 	return nblocks;
 }
@@ -2089,13 +2106,14 @@ allocated:
 	le16_add_cpu(&gdp->bg_free_blocks_count, -num);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
-	if (!EXT4_I(inode)->i_delalloc_reserved_flag && (*count != num)) {
-		/*
-		 * we allocated less blocks than we
-		 * claimed. Add the difference back.
-		 */
-		percpu_counter_add(&sbi->s_freeblocks_counter, *count - num);
-	}
+	percpu_counter_sub(&sbi->s_freeblocks_counter, num);
+	/*
+	 * Now reduce the dirty block count also. Should not go negative
+	 */
+	if (!EXT4_I(inode)->i_delalloc_reserved_flag)
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, *count);
+	else
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, num);
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
 		spin_lock(sb_bgl_lock(sbi, flex_group));
diff --git a/fs/ext4/ext4_sb.h b/fs/ext4/ext4_sb.h
index f20df8a..6d096d5 100644
--- a/fs/ext4/ext4_sb.h
+++ b/fs/ext4/ext4_sb.h
@@ -60,6 +60,7 @@ struct ext4_sb_info {
 	struct percpu_counter s_freeblocks_counter;
 	struct percpu_counter s_freeinodes_counter;
 	struct percpu_counter s_dirs_counter;
+	struct percpu_counter s_dirtyblocks_counter;
 	struct blockgroup_lock s_blockgroup_lock;
 
 	/* root of the per fs reservation window tree */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7a1d2e5..c454fef 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1032,19 +1032,20 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
 	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
 	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
 
-	/* Account for allocated meta_blocks */
-	mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
-
-	/* update fs free blocks counter for truncate case */
-	percpu_counter_add(&sbi->s_freeblocks_counter, mdb_free);
+	if (mdb_free) {
+		/* Account for allocated meta_blocks */
+		mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
+
+		/* update fs dirty blocks counter */
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
+		EXT4_I(inode)->i_allocated_meta_blocks = 0;
+		EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+	}
 
 	/* update per-inode reservations */
 	BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
 	EXT4_I(inode)->i_reserved_data_blocks -= used;
 
-	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
-	EXT4_I(inode)->i_reserved_meta_blocks = mdb;
-	EXT4_I(inode)->i_allocated_meta_blocks = 0;
 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
 	/*
@@ -1609,8 +1610,8 @@ static void ext4_da_release_space(struct inode *inode, int to_free)
 
 	release = to_free + mdb_free;
 
-	/* update fs free blocks counter for truncate case */
-	percpu_counter_add(&sbi->s_freeblocks_counter, release);
+	/* update fs dirty blocks counter for truncate case */
+	percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
 
 	/* update per-inode reservations */
 	BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
@@ -2546,7 +2547,6 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
 	index = pos >> PAGE_CACHE_SHIFT;
 	from = pos & (PAGE_CACHE_SIZE - 1);
 	to = from + len;
-
 retry:
 	/*
 	 * With delayed allocation, we don't log the i_disksize update
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index d9bff44..27bbff9 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3100,7 +3100,7 @@ void exit_ext4_mballoc(void)
  */
 static noinline_for_stack int
 ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
-				handle_t *handle)
+				handle_t *handle, unsigned long reserv_blks)
 {
 	struct buffer_head *bitmap_bh = NULL;
 	struct ext4_super_block *es;
@@ -3188,21 +3188,16 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 	le16_add_cpu(&gdp->bg_free_blocks_count, -ac->ac_b_ex.fe_len);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
 	spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
-
+	percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
 	/*
-	 * free blocks account has already be reduced/reserved
-	 * at write_begin() time for delayed allocation
-	 * do not double accounting
+	 * Now reduce the dirty block count also. Should not go negative
 	 */
-	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED) &&
-			ac->ac_o_ex.fe_len != ac->ac_b_ex.fe_len) {
-		/*
-		 * we allocated less blocks than we calimed
-		 * Add the difference back
-		 */
-		percpu_counter_add(&sbi->s_freeblocks_counter,
-				ac->ac_o_ex.fe_len - ac->ac_b_ex.fe_len);
-	}
+	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
+		/* release all the reserved blocks if non delalloc */
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks);
+	else
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter,
+						ac->ac_b_ex.fe_len);
 
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi,
@@ -4636,12 +4631,13 @@ static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
 ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 				 struct ext4_allocation_request *ar, int *errp)
 {
+	int freed;
 	struct ext4_allocation_context *ac = NULL;
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
 	ext4_fsblk_t block = 0;
-	int freed;
-	int inquota;
+	unsigned long inquota;
+	unsigned long reserv_blks = 0;
 
 	sb = ar->inode->i_sb;
 	sbi = EXT4_SB(sb);
@@ -4659,6 +4655,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 			*errp = -ENOSPC;
 			return 0;
 		}
+		reserv_blks = ar->len;
 	}
 	while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) {
 		ar->flags |= EXT4_MB_HINT_NOPREALLOC;
@@ -4704,7 +4701,7 @@ repeat:
 			ext4_mb_new_preallocation(ac);
 	}
 	if (likely(ac->ac_status == AC_STATUS_FOUND)) {
-		*errp = ext4_mb_mark_diskspace_used(ac, handle);
+		*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_blks);
 		if (*errp ==  -EAGAIN) {
 			/*
 			 * drop the reference that we took
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index db2642a..b17eca6 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -520,6 +520,7 @@ static void ext4_put_super(struct super_block *sb)
 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
 	percpu_counter_destroy(&sbi->s_dirs_counter);
+	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 	brelse(sbi->s_sbh);
 #ifdef CONFIG_QUOTA
 	for (i = 0; i < MAXQUOTAS; i++)
@@ -2279,6 +2280,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		err = percpu_counter_init(&sbi->s_dirs_counter,
 				ext4_count_dirs(sb));
 	}
+	if (!err) {
+		err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
+	}
 	if (err) {
 		printk(KERN_ERR "EXT4-fs: insufficient memory\n");
 		goto failed_mount3;
@@ -2516,6 +2520,7 @@ failed_mount3:
 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
 	percpu_counter_destroy(&sbi->s_dirs_counter);
+	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 failed_mount2:
 	for (i = 0; i < db_count; i++)
 		brelse(sbi->s_group_desc[i]);
@@ -3207,7 +3212,8 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_type = EXT4_SUPER_MAGIC;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
-	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
+	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
+		       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
 	ext4_free_blocks_count_set(es, buf->f_bfree);
 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
 	if (buf->f_bfree < ext4_r_blocks_count(es))
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 05/11] ext4: Retry block reservation

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 030ba6bc67b4f2bc5cd174f57785a1745c929abe upstream.

During block reservation if we don't have enough blocks left, retry
block reservation with smaller block counts.  This makes sure we try
fallocate and DIO with smaller request size and don't fail early.  The
delayed allocation reservation cannot try with smaller block count. So
retry block reservation to handle temporary disk full conditions.  Also
print free blocks details if we fail block allocation during writepages.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/balloc.c  |    8 +++++++-
 fs/ext4/inode.c   |   14 +++++++++++---
 fs/ext4/mballoc.c |    7 ++++++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 6b6b560..532f8cc 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1907,10 +1907,16 @@ ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		if (ext4_claim_free_blocks(sbi, *count)) {
+		while (*count && ext4_claim_free_blocks(sbi, *count)) {
+			/* let others to free the space */
+			yield();
+			*count = *count >> 1;
+		}
+		if (!*count) {
 			*errp = -ENOSPC;
 			return 0;	/*return with ENOSPC error */
 		}
+		num = *count;
 	}
 	/*
 	 * Check quota for allocation of this block.
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c454fef..e82b895 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1549,6 +1549,7 @@ static int ext4_journalled_write_end(struct file *file,
 
 static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
 {
+	int retries = 0;
        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
        unsigned long md_needed, mdblocks, total = 0;
 
@@ -1557,6 +1558,7 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
 	 * in order to allocate nrblocks
 	 * worse case is one extent per block
 	 */
+repeat:
 	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
 	total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
 	mdblocks = ext4_calc_metadata_amount(inode, total);
@@ -1567,6 +1569,10 @@ static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
 
 	if (ext4_claim_free_blocks(sbi, total)) {
 		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
+			yield();
+			goto repeat;
+		}
 		return -ENOSPC;
 	}
 	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
@@ -1864,20 +1870,18 @@ static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
 static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 {
 	int err = 0;
+	struct buffer_head new;
 	struct buffer_head *lbh = &mpd->lbh;
 	sector_t next = lbh->b_blocknr;
-	struct buffer_head new;
 
 	/*
 	 * We consider only non-mapped and non-allocated blocks
 	 */
 	if (buffer_mapped(lbh) && !buffer_delay(lbh))
 		return 0;
-
 	new.b_state = lbh->b_state;
 	new.b_blocknr = 0;
 	new.b_size = lbh->b_size;
-
 	/*
 	 * If we didn't accumulate anything
 	 * to write simply return
@@ -1910,6 +1914,10 @@ static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 				  lbh->b_size >> mpd->inode->i_blkbits, err);
 		printk(KERN_EMERG "This should not happen.!! "
 					"Data will be lost\n");
+		if (err == -ENOSPC) {
+			printk(KERN_CRIT "Total free blocks count %lld\n",
+				ext4_count_free_blocks(mpd->inode->i_sb));
+		}
 		/* invlaidate all the pages */
 		ext4_da_block_invalidatepages(mpd, next,
 				lbh->b_size >> mpd->inode->i_blkbits);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 27bbff9..453589d 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4651,7 +4651,12 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		if (ext4_claim_free_blocks(sbi, ar->len)) {
+		while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
+			/* let others to free the space */
+			yield();
+			ar->len = ar->len >> 1;
+		}
+		if (!ar->len) {
 			*errp = -ENOSPC;
 			return 0;
 		}
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 06/11] ext4: Retry block allocation if we have free blocks left

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit df22291ff0fde0d350cf15dac3e5cc33ac528875 upstream.

When we truncate files, the meta-data blocks released are not reused
untill we commit the truncate transaction.  That means delayed get_block
request will return ENOSPC even if we have free blocks left.  Force a
journal commit and retry block allocation if we get ENOSPC with free
blocks left.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/inode.c |   81 ++++++++++++++++++++++++++++++++++++++----------------
 1 files changed, 57 insertions(+), 24 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e82b895..71901ae 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1661,6 +1661,7 @@ struct mpage_da_data {
 	struct writeback_control *wbc;
 	int io_done;
 	long pages_written;
+	int retval;
 };
 
 /*
@@ -1858,6 +1859,24 @@ static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
 	return;
 }
 
+static void ext4_print_free_blocks(struct inode *inode)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	printk(KERN_EMERG "Total free blocks count %lld\n",
+			ext4_count_free_blocks(inode->i_sb));
+	printk(KERN_EMERG "Free/Dirty block details\n");
+	printk(KERN_EMERG "free_blocks=%lld\n",
+			percpu_counter_sum(&sbi->s_freeblocks_counter));
+	printk(KERN_EMERG "dirty_blocks=%lld\n",
+			percpu_counter_sum(&sbi->s_dirtyblocks_counter));
+	printk(KERN_EMERG "Block reservation details\n");
+	printk(KERN_EMERG "i_reserved_data_blocks=%lu\n",
+			EXT4_I(inode)->i_reserved_data_blocks);
+	printk(KERN_EMERG "i_reserved_meta_blocks=%lu\n",
+			EXT4_I(inode)->i_reserved_meta_blocks);
+	return;
+}
+
 /*
  * mpage_da_map_blocks - go through given space
  *
@@ -1872,7 +1891,7 @@ static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 	int err = 0;
 	struct buffer_head new;
 	struct buffer_head *lbh = &mpd->lbh;
-	sector_t next = lbh->b_blocknr;
+	sector_t next;
 
 	/*
 	 * We consider only non-mapped and non-allocated blocks
@@ -1882,6 +1901,7 @@ static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 	new.b_state = lbh->b_state;
 	new.b_blocknr = 0;
 	new.b_size = lbh->b_size;
+	next = lbh->b_blocknr;
 	/*
 	 * If we didn't accumulate anything
 	 * to write simply return
@@ -1898,6 +1918,13 @@ static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 		 */
 		if (err == -EAGAIN)
 			return 0;
+
+		if (err == -ENOSPC &&
+				ext4_count_free_blocks(mpd->inode->i_sb)) {
+			mpd->retval = err;
+			return 0;
+		}
+
 		/*
 		 * get block failure will cause us
 		 * to loop in writepages. Because
@@ -1915,8 +1942,7 @@ static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 		printk(KERN_EMERG "This should not happen.!! "
 					"Data will be lost\n");
 		if (err == -ENOSPC) {
-			printk(KERN_CRIT "Total free blocks count %lld\n",
-				ext4_count_free_blocks(mpd->inode->i_sb));
+			ext4_print_free_blocks(mpd->inode);
 		}
 		/* invlaidate all the pages */
 		ext4_da_block_invalidatepages(mpd, next,
@@ -2141,39 +2167,36 @@ static int __mpage_da_writepage(struct page *page,
  */
 static int mpage_da_writepages(struct address_space *mapping,
 			       struct writeback_control *wbc,
-			       get_block_t get_block)
+			       struct mpage_da_data *mpd)
 {
-	struct mpage_da_data mpd;
 	long to_write;
 	int ret;
 
-	if (!get_block)
+	if (!mpd->get_block)
 		return generic_writepages(mapping, wbc);
 
-	mpd.wbc = wbc;
-	mpd.inode = mapping->host;
-	mpd.lbh.b_size = 0;
-	mpd.lbh.b_state = 0;
-	mpd.lbh.b_blocknr = 0;
-	mpd.first_page = 0;
-	mpd.next_page = 0;
-	mpd.get_block = get_block;
-	mpd.io_done = 0;
-	mpd.pages_written = 0;
+	mpd->lbh.b_size = 0;
+	mpd->lbh.b_state = 0;
+	mpd->lbh.b_blocknr = 0;
+	mpd->first_page = 0;
+	mpd->next_page = 0;
+	mpd->io_done = 0;
+	mpd->pages_written = 0;
+	mpd->retval = 0;
 
 	to_write = wbc->nr_to_write;
 
-	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, &mpd);
+	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);
 
 	/*
 	 * Handle last extent of pages
 	 */
-	if (!mpd.io_done && mpd.next_page != mpd.first_page) {
-		if (mpage_da_map_blocks(&mpd) == 0)
-			mpage_da_submit_io(&mpd);
+	if (!mpd->io_done && mpd->next_page != mpd->first_page) {
+		if (mpage_da_map_blocks(mpd) == 0)
+			mpage_da_submit_io(mpd);
 	}
 
-	wbc->nr_to_write = to_write - mpd.pages_written;
+	wbc->nr_to_write = to_write - mpd->pages_written;
 	return ret;
 }
 
@@ -2420,6 +2443,7 @@ static int ext4_da_writepages(struct address_space *mapping,
 {
 	handle_t *handle = NULL;
 	loff_t range_start = 0;
+	struct mpage_da_data mpd;
 	struct inode *inode = mapping->host;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
 	long to_write, pages_skipped = 0;
@@ -2467,6 +2491,9 @@ static int ext4_da_writepages(struct address_space *mapping,
 	range_start =  wbc->range_start;
 	pages_skipped = wbc->pages_skipped;
 
+	mpd.wbc = wbc;
+	mpd.inode = mapping->host;
+
 restart_loop:
 	to_write = wbc->nr_to_write;
 	while (!ret && to_write > 0) {
@@ -2502,11 +2529,17 @@ restart_loop:
 				goto out_writepages;
 			}
 		}

[PATCH 2.6.27.y 07/11] ext4: Use tag dirty lookup during mpage_da_submit_io

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit af6f029d3836eb7264cd3fbb13a6baf0e5fdb5ea upstream.

This enables us to drop the range_cont writeback mode
use from ext4_da_writepages.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/inode.c |   30 +++++++++++++-----------------
 1 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 71901ae..a67f837 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1699,17 +1699,23 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
 
 	pagevec_init(&pvec, 0);
 	while (index <= end) {
-		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+		/*
+		 * We can use PAGECACHE_TAG_DIRTY lookup here because
+		 * even though we have cleared the dirty flag on the page
+		 * We still keep the page in the radix tree with tag
+		 * PAGECACHE_TAG_DIRTY. See clear_page_dirty_for_io.
+		 * The PAGECACHE_TAG_DIRTY is cleared in set_page_writeback
+		 * which is called via the below writepage callback.
+		 */
+		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+					PAGECACHE_TAG_DIRTY,
+					min(end - index,
+					(pgoff_t)PAGEVEC_SIZE-1) + 1);
 		if (nr_pages == 0)
 			break;
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pvec.pages[i];
 
-			index = page->index;
-			if (index > end)
-				break;
-			index++;
-
 			BUG_ON(!PageLocked(page));
 			BUG_ON(PageWriteback(page));
 
@@ -2442,7 +2448,6 @@ static int ext4_da_writepages(struct address_space *mapping,
 			      struct writeback_control *wbc)
 {
 	handle_t *handle = NULL;
-	loff_t range_start = 0;
 	struct mpage_da_data mpd;
 	struct inode *inode = mapping->host;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
@@ -2481,14 +2486,7 @@ static int ext4_da_writepages(struct address_space *mapping,
 		wbc->nr_to_write = sbi->s_mb_stream_request;
 	}
 
-	if (!wbc->range_cyclic)
-		/*
-		 * If range_cyclic is not set force range_cont
-		 * and save the old writeback_index
-		 */
-		wbc->range_cont = 1;
 
-	range_start =  wbc->range_start;
 	pages_skipped = wbc->pages_skipped;
 
 	mpd.wbc = wbc;
@@ -2559,9 +2557,8 @@ restart_loop:
 		wbc->nr_to_write = to_write;
 	}
 
-	if (wbc->range_cont && (pages_skipped != wbc->pages_skipped)) {
+	if (!wbc->range_cyclic && (pages_skipped != wbc->pages_skipped)) {
 		/* We skipped pages in this loop */
-		wbc->range_start = range_start;
 		wbc->nr_to_write = to_write +
 				wbc->pages_skipped - pages_skipped;
 		wbc->pages_skipped = pages_skipped;
@@ -2570,7 +2567,6 @@ restart_loop:
 
 out_writepages:
 	wbc->nr_to_write = to_write - nr_to_writebump;
-	wbc->range_start = range_start;
 	return ret;
 }
 
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 08/11] vfs: Remove the range_cont writeback mode.

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 74baaaaec8b4f22e1ae279f5ecca4ff705b28912 upstream.

Ext4 was the only user of range_cont writeback mode and ext4 switched
to a different method. So remove the range_cont mode which is not used
in the kernel.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 include/linux/writeback.h |    1 -
 mm/page-writeback.c       |    2 --
 2 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index c2835bb..cc0e6d9 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -62,7 +62,6 @@ struct writeback_control {
 	unsigned for_writepages:1;	/* This is a writepages() call */
 	unsigned range_cyclic:1;	/* range_start is cyclic */
 	unsigned more_io:1;		/* more io to be dispatched */
-	unsigned range_cont:1;
 };
 
 /*
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 5f7cdc2..e5c4ca2 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1027,8 +1027,6 @@ continue_unlock:
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		mapping->writeback_index = done_index;
 
-	if (wbc->range_cont)
-		wbc->range_start = index << PAGE_CACHE_SHIFT;
 	return ret;
 }
 EXPORT_SYMBOL(write_cache_pages);
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 09/11] vfs: Add no_nrwrite_index_update writeback control flag

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 17bc6c30cf6bfffd816bdc53682dd46fc34a2cf4 upstream.

If no_nrwrite_index_update is set we don't update nr_to_write and
address space writeback_index in write_cache_pages.  This change
enables a file system to skip these updates in write_cache_pages and do
them in the writepages() callback.  This patch will be followed by an
ext4 patch that make use of these new flags.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
CC: linux-fsdevel@vger.kernel.org
[dev@jaysonking.com: Modified the patch to account for subsequent changes in mainline being cherry-picked earlier for 2.6.27.y.]
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 include/linux/writeback.h |    9 +++++++++
 mm/page-writeback.c       |   14 +++++++++-----
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index cc0e6d9..b93ab38 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -62,6 +62,15 @@ struct writeback_control {
 	unsigned for_writepages:1;	/* This is a writepages() call */
 	unsigned range_cyclic:1;	/* range_start is cyclic */
 	unsigned more_io:1;		/* more io to be dispatched */
+	/*
+	 * write_cache_pages() won't update wbc->nr_to_write and
+	 * mapping->writeback_index if no_nrwrite_index_update
+	 * is set.  write_cache_pages() may write more than we
+	 * requested and we want to make sure nr_to_write and
+	 * writeback_index are updated in a consistent manner
+	 * so we use a single control to update them
+	 */
+	unsigned no_nrwrite_index_update:1;
 };
 
 /*
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e5c4ca2..036dee5 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -878,6 +878,7 @@ int write_cache_pages(struct address_space *mapping,
 	pgoff_t done_index;
 	int cycled;
 	int range_whole = 0;
+	long nr_to_write = wbc->nr_to_write;
 
 	if (wbc->nonblocking && bdi_write_congested(bdi)) {
 		wbc->encountered_congestion = 1;
@@ -985,9 +986,9 @@ continue_unlock:
 				}
  			}
 
-			if (wbc->nr_to_write > 0) {
-				wbc->nr_to_write--;
-				if (wbc->nr_to_write == 0 &&
+			if (nr_to_write > 0) {
+				nr_to_write--;
+				if (nr_to_write == 0 &&
 				    wbc->sync_mode == WB_SYNC_NONE) {
 					/*
 					 * We stop writing back only if we are
@@ -1024,8 +1025,11 @@ continue_unlock:
 		end = writeback_index - 1;
 		goto retry;
 	}
-	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
-		mapping->writeback_index = done_index;
+	if (!wbc->no_nrwrite_index_update) {
+		if (wbc->range_cyclic || (range_whole && nr_to_write > 0))
+			mapping->writeback_index = done_index;
+		wbc->nr_to_write = nr_to_write;
+	}
 
 	return ret;
 }
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 10/11] ext4: Fix file fragmentation during large file write.

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 22208dedbd7626e5fc4339c417f8d24cc21f79d7 upstream.

The range_cyclic writeback mode uses the address_space writeback_index
as the start index for writeback.  With delayed allocation we were
updating writeback_index wrongly resulting in highly fragmented file.
This patch reduces the number of extents reduced from 4000 to 27 for a
3GB file.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[dev@jaysonking.com: Some changed lines from the original version of this patch were dropped, since they were rolled up with another cherry-picked patch applied to 2.6.27.y earlier.]
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/inode.c |   88 ++++++++++++++++++++++++++++++++++--------------------
 1 files changed, 55 insertions(+), 33 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a67f837..658ddef 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1721,7 +1721,11 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
 
 			pages_skipped = mpd->wbc->pages_skipped;
 			err = mapping->a_ops->writepage(page, mpd->wbc);
-			if (!err)
+			if (!err && (pages_skipped == mpd->wbc->pages_skipped))
+				/*
+				 * have successfully written the page
+				 * without skipping the same
+				 */
 				mpd->pages_written++;
 			/*
 			 * In error case, we have to continue because
@@ -2175,7 +2179,6 @@ static int mpage_da_writepages(struct address_space *mapping,
 			       struct writeback_control *wbc,
 			       struct mpage_da_data *mpd)
 {
-	long to_write;
 	int ret;
 
 	if (!mpd->get_block)
@@ -2190,19 +2193,18 @@ static int mpage_da_writepages(struct address_space *mapping,
 	mpd->pages_written = 0;
 	mpd->retval = 0;
 
-	to_write = wbc->nr_to_write;
-
 	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);
-
 	/*
 	 * Handle last extent of pages
 	 */
 	if (!mpd->io_done && mpd->next_page != mpd->first_page) {
 		if (mpage_da_map_blocks(mpd) == 0)
 			mpage_da_submit_io(mpd);
-	}
 
-	wbc->nr_to_write = to_write - mpd->pages_written;
+		mpd->io_done = 1;
+		ret = MPAGE_DA_EXTENT_TAIL;
+	}
+	wbc->nr_to_write -= mpd->pages_written;
 	return ret;
 }
 
@@ -2447,11 +2449,14 @@ static int ext4_da_writepages_trans_blocks(struct inode *inode)
 static int ext4_da_writepages(struct address_space *mapping,
 			      struct writeback_control *wbc)
 {
+	pgoff_t	index;
+	int range_whole = 0;
 	handle_t *handle = NULL;
 	struct mpage_da_data mpd;
 	struct inode *inode = mapping->host;
+	int no_nrwrite_index_update;
+	long pages_written = 0, pages_skipped;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
-	long to_write, pages_skipped = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
 
 	/*
@@ -2485,16 +2490,26 @@ static int ext4_da_writepages(struct address_space *mapping,
 		nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
 		wbc->nr_to_write = sbi->s_mb_stream_request;
 	}
+	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+		range_whole = 1;
 
-
-	pages_skipped = wbc->pages_skipped;
+	if (wbc->range_cyclic)
+		index = mapping->writeback_index;
+	else
+		index = wbc->range_start >> PAGE_CACHE_SHIFT;
 
 	mpd.wbc = wbc;
 	mpd.inode = mapping->host;
 
-restart_loop:
-	to_write = wbc->nr_to_write;
-	while (!ret && to_write > 0) {
+	/*
+	 * we don't want write_cache_pages to update
+	 * nr_to_write and writeback_index
+	 */
+	no_nrwrite_index_update = wbc->no_nrwrite_index_update;
+	wbc->no_nrwrite_index_update = 1;
+	pages_skipped = wbc->pages_skipped;
+
+	while (!ret && wbc->nr_to_write > 0) {
 
 		/*
 		 * we  insert one extent at a time. So we need
@@ -2527,46 +2542,53 @@ restart_loop:
 				goto out_writepages;
 			}
 		}
-		to_write -= wbc->nr_to_write;
-
 		mpd.get_block = ext4_da_get_block_write;
 		ret = mpage_da_writepages(mapping, wbc, &mpd);
 
 		ext4_journal_stop(handle);
 
-		if (mpd.retval == -ENOSPC)
+		if (mpd.retval == -ENOSPC) {
+			/* commit the transaction which would
+			 * free blocks released in the transaction
+			 * and try again
+			 */
 			jbd2_journal_force_commit_nested(sbi->s_journal);
-
-		/* reset the retry count */
-		if (ret == MPAGE_DA_EXTENT_TAIL) {
+			wbc->pages_skipped = pages_skipped;
+			ret = 0;
+		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
 			/*
 			 * got one extent now try with
 			 * rest of the pages
 			 */
-			to_write += wbc->nr_to_write;
+			pages_written += mpd.pages_written;
+			wbc->pages_skipped = pages_skipped;
 			ret = 0;
-		} else if (wbc->nr_to_write) {
+		} else if (wbc->nr_to_write)
 			/*
 			 * There is no more writeout needed
 			 * or we requested for a noblocking writeout
 			 * and we found the device congested
 			 */
-			to_write += wbc->nr_to_write;
 			break;
-		}
-		wbc->nr_to_write = to_write;
-	}
-
-	if (!wbc->range_cyclic && (pages_skipped != wbc->pages_skipped)) {
-		/* We skipped pages in this loop */
-		wbc->nr_to_write = to_write +
-				wbc->pages_skipped - pages_skipped;
-		wbc->pages_skipped = pages_skipped;
-		goto restart_loop;
 	}
+	if (pages_skipped != wbc->pages_skipped)
+		printk(KERN_EMERG "This should not happen leaving %s "
+				"with nr_to_write = %ld ret = %d\n",
+				__func__, wbc->nr_to_write, ret);
+
+	/* Update index */
+	index += pages_written;
+	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+		/*
+		 * set the writeback_index so that range_cyclic
+		 * mode will write it back later
+		 */
+		mapping->writeback_index = index;
 
 out_writepages:
-	wbc->nr_to_write = to_write - nr_to_writebump;
+	if (!no_nrwrite_index_update)
+		wbc->no_nrwrite_index_update = 0;
+	wbc->nr_to_write -= nr_to_writebump;
 	return ret;
 }
 
-- 
1.6.6.1.1.g974db.dirty

[PATCH 2.6.27.y 11/11] ext4: Implement range_cyclic in ext4_da_writepages instead of write_cache_pages

[Theodore Ts'o]

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 2acf2c261b823d9d9ed954f348b97620297a36b5 upstream.

With delayed allocation we lock the page in write_cache_pages() and
try to build an in memory extent of contiguous blocks.  This is needed
so that we can get large contiguous blocks request.  If range_cyclic
mode is enabled, write_cache_pages() will loop back to the 0 index if
no I/O has been done yet, and try to start writing from the beginning
of the range.  That causes an attempt to take the page lock of lower
index page while holding the page lock of higher index page, which can
cause a dead lock with another writeback thread.

The solution is to implement the range_cyclic behavior in
ext4_da_writepages() instead.

http://bugzilla.kernel.org/show_bug.cgi?id=12579

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/inode.c |   21 +++++++++++++++++++--
 1 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 658ddef..0e4286a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2456,6 +2456,7 @@ static int ext4_da_writepages(struct address_space *mapping,
 	struct inode *inode = mapping->host;
 	int no_nrwrite_index_update;
 	long pages_written = 0, pages_skipped;
+	int range_cyclic, cycled = 1, io_done = 0;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
 
@@ -2493,9 +2494,15 @@ static int ext4_da_writepages(struct address_space *mapping,
 	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 		range_whole = 1;
 
-	if (wbc->range_cyclic)
+	range_cyclic = wbc->range_cyclic;
+	if (wbc->range_cyclic) {
 		index = mapping->writeback_index;
-	else
+		if (index)
+			cycled = 0;
+		wbc->range_start = index << PAGE_CACHE_SHIFT;
+		wbc->range_end  = LLONG_MAX;
+		wbc->range_cyclic = 0;
+	} else
 		index = wbc->range_start >> PAGE_CACHE_SHIFT;
 
 	mpd.wbc = wbc;
@@ -2509,6 +2516,7 @@ static int ext4_da_writepages(struct address_space *mapping,
 	wbc->no_nrwrite_index_update = 1;
 	pages_skipped = wbc->pages_skipped;
 
+retry:
 	while (!ret && wbc->nr_to_write > 0) {
 
 		/*
@@ -2563,6 +2571,7 @@ static int ext4_da_writepages(struct address_space *mapping,
 			pages_written += mpd.pages_written;
 			wbc->pages_skipped = pages_skipped;
 			ret = 0;
+			io_done = 1;
 		} else if (wbc->nr_to_write)
 			/*
 			 * There is no more writeout needed
@@ -2571,6 +2580,13 @@ static int ext4_da_writepages(struct address_space *mapping,
 			 */
 			break;
 	}
+	if (!io_done && !cycled) {
+		cycled = 1;
+		index = 0;
+		wbc->range_start = index << PAGE_CACHE_SHIFT;
+		wbc->range_end  = mapping->writeback_index - 1;
+		goto retry;
+	}
 	if (pages_skipped != wbc->pages_skipped)
 		printk(KERN_EMERG "This should not happen leaving %s "
 				"with nr_to_write = %ld ret = %d\n",
@@ -2578,6 +2594,7 @@ static int ext4_da_writepages(struct address_space *mapping,
 
 	/* Update index */
 	index += pages_written;
+	wbc->range_cyclic = range_cyclic;
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		/*
 		 * set the writeback_index so that range_cyclic
-- 
1.6.6.1.1.g974db.dirty

Re: [PATCH 2.6.27.y 04/11] ext4: Add percpu dirty block accounting.

[Andreas Dilger]

[-- Attachment #1: Type: text/plain, Size: 1501 bytes --]

On 2010-03-15, at 18:25, Theodore Ts'o wrote:
> int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
> 						ext4_fsblk_t nblocks)
> {
> +	if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
> +						EXT4_FREEBLOCKS_WATERMARK) {
> +		free_blocks  = percpu_counter_sum(fbc);
> +		dirty_blocks = percpu_counter_sum(dbc);
> +		if (dirty_blocks < 0) {
> +			printk(KERN_CRIT "Dirty block accounting "
> +					"went wrong %lld\n",
> +					dirty_blocks);

Just looking at this old patch, and noticed this is still the same in  
newer versions.

This should probably be either an ext4_error(), since it affects data  
correctness, even though it isn't an on-disk error, or at least an  
ext4_msg() so that it also prints the block device and uses the  
standard ext4 error format.

As it stands, this error doesn't indicate that it is an ext4 error, or  
which filesystem is involved, so it isn't very useful to the  
sysadmin.  I don't think it is needed for the .stable release, but  
would be good for the next kernel.

In the first patch (ext4-claim-err.diff) the access to the superblock  
for ext4_msg() is a bit of a hack, but I think it isn't terrible.

The second patch (ext4-error-cleanup.diff, to be used instead of the  
first one) is a bit more thorough cleanup that changes the callers to  
pass a struct super_block, and also removes some single-use stack  
variables in related code.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

[-- Attachment #2: ext4-claim-err.diff --]
[-- Type: application/octet-stream, Size: 740 bytes --]

Use a standard ext4 error message format for ext4_has_free_blocks().

Signed-off-by: Andreas Dilger <adilger@sun.com>

--- ./fs/ext4/balloc.c.orig	2009-09-09 16:13:59.000000000 -0600
+++ ./fs/ext4/balloc.c	2010-03-16 10:57:50.000000000 -0600
@@ -559,9 +559,9 @@ int ext4_has_free_blocks(struct ext4_sb_
 		free_blocks  = percpu_counter_sum_positive(fbc);
 		dirty_blocks = percpu_counter_sum_positive(dbc);
 		if (dirty_blocks < 0) {
-			printk(KERN_CRIT "Dirty block accounting "
-					"went wrong %lld\n",
-					(long long)dirty_blocks);
+			ext4_msg(sbi->s_buddy_cache->i_sb, KERN_CRIT,
+				 "Dirty block accounting went wrong: %lld\n",
+				 (long long)dirty_blocks);
 		}
 	}
 	/* Check whether we have space after

[-- Attachment #3: ext4-error-cleanup.diff --]
[-- Type: application/octet-stream, Size: 5673 bytes --]

Pass struct superblock to ext4_has_free_blocks() so that it can use ext4_msg()
for the error message, and mark static, since it is only used inside balloc.c.

Signed-off-by: Andreas Dilger <adilger@sun.com>

--- ./fs/ext4/balloc.c.orig	2009-09-09 16:13:59.000000000 -0600
+++ ./fs/ext4/balloc.c	2010-03-16 12:13:17.000000000 -0600
@@ -538,15 +538,16 @@ void ext4_free_blocks(handle_t *handle, 
 
 /**
  * ext4_has_free_blocks()
- * @sbi:	in-core super block structure.
+ * @sb:		in-core super block structure.
  * @nblocks:	number of needed blocks
  *
  * Check if filesystem has nblocks free & available for allocation.
  * On success return 1, return 0 on failure.
  */
-int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
+static int ext4_has_free_blocks(struct super_block *sb, s64 nblocks)
 {
 	s64 free_blocks, dirty_blocks, root_blocks;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
 	struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
 
@@ -559,9 +560,9 @@ int ext4_has_free_blocks(struct ext4_sb_
 		free_blocks  = percpu_counter_sum_positive(fbc);
 		dirty_blocks = percpu_counter_sum_positive(dbc);
 		if (dirty_blocks < 0) {
-			printk(KERN_CRIT "Dirty block accounting "
-					"went wrong %lld\n",
-					(long long)dirty_blocks);
+			ext4_msg(sb, KERN_CRIT,
+				 "Dirty block accounting went wrong: %lld\n",
+				 (long long)dirty_blocks);
 		}
 	}
 	/* Check whether we have space after
@@ -581,11 +582,10 @@ int ext4_has_free_blocks(struct ext4_sb_
 	return 0;
 }
 
-int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
-						s64 nblocks)
+int ext4_claim_free_blocks(struct super_block *sb, s64 nblocks)
 {
-	if (ext4_has_free_blocks(sbi, nblocks)) {
-		percpu_counter_add(&sbi->s_dirtyblocks_counter, nblocks);
+	if (ext4_has_free_blocks(sb, nblocks)) {
+		percpu_counter_add(&EXT4_SB(sb)->s_dirtyblocks_counter, nblocks);
 		return 0;
 	} else
 		return -ENOSPC;
@@ -605,8 +605,7 @@ int ext4_claim_free_blocks(struct ext4_s
  */
 int ext4_should_retry_alloc(struct super_block *sb, int *retries)
 {
-	if (!ext4_has_free_blocks(EXT4_SB(sb), 1) ||
-	    (*retries)++ > 3 ||
+	if (!ext4_has_free_blocks(sb, 1) || (*retries)++ > 3 ||
 	    !EXT4_SB(sb)->s_journal)
 		return 0;
 
--- ./fs/ext4/ext4.h.orig	2009-09-09 16:13:59.000000000 -0600
+++ ./fs/ext4/ext4.h	2010-03-16 12:14:04.000000000 -0600
@@ -1274,8 +1274,7 @@ extern unsigned long ext4_bg_num_gdb(str
 			ext4_group_t group);
 extern ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t goal, unsigned long *count, int *errp);
-extern int ext4_claim_free_blocks(struct ext4_sb_info *sbi, s64 nblocks);
-extern int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks);
+extern int ext4_claim_free_blocks(struct super_block *sb, s64 nblocks);
 extern void ext4_free_blocks(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t block, unsigned long count, int metadata);
 extern void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
--- ./fs/ext4/inode.c.orig	2009-09-09 16:13:59.000000000 -0600
+++ ./fs/ext4/inode.c	2010-03-16 12:16:20.000000000 -0600
@@ -1747,7 +1747,6 @@ static int ext4_journalled_write_end(str
 static int ext4_da_reserve_space(struct inode *inode, sector_t lblock)
 {
 	int retries = 0;
-	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	struct ext4_inode_info *ei = EXT4_I(inode);
 	unsigned long md_needed, md_reserved;
 	int ret;
@@ -1774,7 +1773,7 @@ repeat:
 	if (ret)
 		return ret;
 
-	if (ext4_claim_free_blocks(sbi, md_needed + 1)) {
+	if (ext4_claim_free_blocks(inode->i_sb, md_needed + 1)) {
 		dquot_release_reservation_block(inode, md_needed + 1);
 		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
 			yield();
@@ -1792,7 +1791,6 @@ repeat:
 
 static void ext4_da_release_space(struct inode *inode, int to_free)
 {
-	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	struct ext4_inode_info *ei = EXT4_I(inode);
 
 	if (!to_free)
@@ -1825,7 +1823,7 @@ static void ext4_da_release_space(struct
 	}
 
 	/* update fs dirty blocks counter */
-	percpu_counter_sub(&sbi->s_dirtyblocks_counter, to_free);
+	percpu_counter_sub(&EXT4_SB(sb)->s_dirtyblocks_counter, to_free);
 
 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
--- ./fs/ext4/mballoc.c.orig	2009-09-09 16:13:59.000000000 -0600
+++ ./fs/ext4/mballoc.c	2010-03-16 12:19:49.000000000 -0600
@@ -4463,14 +4463,12 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
 {
 	int freed;
 	struct ext4_allocation_context *ac = NULL;
-	struct ext4_sb_info *sbi;
 	struct super_block *sb;
 	ext4_fsblk_t block = 0;
 	unsigned int inquota = 0;
 	unsigned int reserv_blks = 0;
 
 	sb = ar->inode->i_sb;
-	sbi = EXT4_SB(sb);
 
 	trace_ext4_request_blocks(ar);
 
@@ -4486,7 +4484,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
 		 * there is enough free blocks to do block allocation
 		 * and verify allocation doesn't exceed the quota limits.
 		 */
-		while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
+		while (ar->len && ext4_claim_free_blocks(sb, ar->len)) {
 			/* let others to free the space */
 			yield();
 			ar->len = ar->len >> 1;
@@ -4577,8 +4575,8 @@ out3:
 	if (!ar->len) {
 		if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag)
 			/* release all the reserved blocks if non delalloc */
-			percpu_counter_sub(&sbi->s_dirtyblocks_counter,
-						reserv_blks);
+			percpu_counter_sub(&EXT4_SB(sb)->s_dirtyblocks_counter,
+					   reserv_blks);
 	}
 
 	trace_ext4_allocate_blocks(ar, (unsigned long long)block);

Re: [PATCH 2.6.27.y 04/11] ext4: Add percpu dirty block accounting.

[tytso]

On Tue, Mar 16, 2010 at 12:48:03PM -0600, Andreas Dilger wrote:
> 
> Just looking at this old patch, and noticed this is still the same
> in newer versions.
> 
> This should probably be either an ext4_error(), since it affects
> data correctness, even though it isn't an on-disk error, or at least
> an ext4_msg() so that it also prints the block device and uses the
> standard ext4 error format.

Yeah, we should convert it to use ext4_msg(); using ext4_error()
doesn't seem appropriate since that will mark the file system as
corrupted, which isn't the case if this isn't an on-disk error.  Maybe
a WARN_ON(1) is appropriate so that we get a stack trace and
kerneloops.org tracking?

> In the first patch (ext4-claim-err.diff) the access to the
> superblock for ext4_msg() is a bit of a hack, but I think it isn't
> terrible.

Agreed, this isn't bad.

> The second patch (ext4-error-cleanup.diff, to be used instead of the
> first one) is a bit more thorough cleanup that changes the callers
> to pass a struct super_block, and also removes some single-use stack
> variables in related code.

I haven't looked closely at this one yet, I'm not entirely convinced
the cleanups are worth all of the changes, but I'm willing to be
convinced.

					- Ted

Re: [PATCH 2.6.27.y 00/11] *** SUBJECT HERE ***

[Jayson R. King]

On 03/15/2010 07:25 PM, Theodore Ts'o wrote:
> These are the patches backported by Jayson R. King.  I've eyeballed
> them, and run them through a xfsqa test run, and they look good to me.
> 
> Greg, please apply them to the 2.6.27 kernel.
> 
>       	     	   					- Ted
> 
> Aneesh Kumar K.V (10):
>   ext4: invalidate pages if delalloc block allocation fails.
>   ext4: Make sure all the block allocation paths reserve blocks
>   ext4: Add percpu dirty block accounting.
>   ext4: Retry block reservation
>   ext4: Retry block allocation if we have free blocks left
>   ext4: Use tag dirty lookup during mpage_da_submit_io
>   vfs: Remove the range_cont writeback mode.
>   vfs: Add no_nrwrite_index_update writeback control flag
>   ext4: Fix file fragmentation during large file write.
>   ext4: Implement range_cyclic in ext4_da_writepages instead of
>     write_cache_pages
> 
> Mingming Cao (1):
>   percpu counter: clean up percpu_counter_sum_and_set()
> 
>  fs/ext4/balloc.c               |   88 +++++++++---
>  fs/ext4/ext4.h                 |   13 ++
>  fs/ext4/ext4_sb.h              |    1 +
>  fs/ext4/inode.c                |  314 ++++++++++++++++++++++++++++------------
>  fs/ext4/mballoc.c              |   39 +++--
>  fs/ext4/super.c                |    8 +-
>  include/linux/percpu_counter.h |   12 +-
>  include/linux/writeback.h      |   10 +-
>  lib/percpu_counter.c           |    8 +-
>  mm/page-writeback.c            |   16 +-
>  10 files changed, 360 insertions(+), 149 deletions(-)

Thanks for looking at this.

Jayson

patch ext4-add-percpu-dirty-block-accounting.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: Add percpu dirty block accounting.

to the 2.6.27-stable tree.  Its filename is

    ext4-add-percpu-dirty-block-accounting.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:21:01 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:25:58 -0400
Subject: ext4: Add percpu dirty block accounting.
To: stable@kernel.org
Cc: "Theodore Ts'o" <tytso@mit.edu>, Ext4 Developers List <linux-ext4@vger.kernel.org>, Mingming Cao <cmm@us.ibm.com>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-5-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 6bc6e63fcd7dac9e633ea29f1fddd9580ab28f3f upstream.

This patch adds dirty block accounting using percpu_counters.  Delayed
allocation block reservation is now done by updating dirty block
counter.  In a later patch we switch to non delalloc mode if the
filesystem free blocks is greater than 150% of total filesystem dirty
blocks

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao<cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 fs/ext4/balloc.c  |   62 ++++++++++++++++++++++++++++++++++--------------------
 fs/ext4/ext4_sb.h |    1 
 fs/ext4/inode.c   |   22 +++++++++----------
 fs/ext4/mballoc.c |   31 ++++++++++++---------------
 fs/ext4/super.c   |    8 ++++++
 5 files changed, 73 insertions(+), 51 deletions(-)

--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1757,26 +1757,38 @@ out:
 int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
 						ext4_fsblk_t nblocks)
 {
-	s64 free_blocks;
+	s64 free_blocks, dirty_blocks;
 	ext4_fsblk_t root_blocks = 0;
 	struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+	struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
 
-	free_blocks = percpu_counter_read(fbc);
+	free_blocks  = percpu_counter_read_positive(fbc);
+	dirty_blocks = percpu_counter_read_positive(dbc);
 
 	if (!capable(CAP_SYS_RESOURCE) &&
 		sbi->s_resuid != current->fsuid &&
 		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
 		root_blocks = ext4_r_blocks_count(sbi->s_es);
 
-	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
-		free_blocks = percpu_counter_sum(&sbi->s_freeblocks_counter);
-
-	if (free_blocks < (root_blocks + nblocks))
+	if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
+						EXT4_FREEBLOCKS_WATERMARK) {
+		free_blocks  = percpu_counter_sum(fbc);
+		dirty_blocks = percpu_counter_sum(dbc);
+		if (dirty_blocks < 0) {
+			printk(KERN_CRIT "Dirty block accounting "
+					"went wrong %lld\n",
+					dirty_blocks);
+		}
+	}
+	/* Check whether we have space after
+	 * accounting for current dirty blocks
+	 */
+	if (free_blocks < ((s64)(root_blocks + nblocks) + dirty_blocks))
 		/* we don't have free space */
 		return -ENOSPC;
 
-	/* reduce fs free blocks counter */
-	percpu_counter_sub(fbc, nblocks);
+	/* Add the blocks to nblocks */
+	percpu_counter_add(dbc, nblocks);
 	return 0;
 }
 
@@ -1792,23 +1804,28 @@ int ext4_claim_free_blocks(struct ext4_s
 ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
 						ext4_fsblk_t nblocks)
 {
-	ext4_fsblk_t free_blocks;
+	ext4_fsblk_t free_blocks, dirty_blocks;
 	ext4_fsblk_t root_blocks = 0;
+	struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+	struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
 
-	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+	free_blocks  = percpu_counter_read_positive(fbc);
+	dirty_blocks = percpu_counter_read_positive(dbc);
 
 	if (!capable(CAP_SYS_RESOURCE) &&
 		sbi->s_resuid != current->fsuid &&
 		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
 		root_blocks = ext4_r_blocks_count(sbi->s_es);
 
-	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
-		free_blocks = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
-
-	if (free_blocks <= root_blocks)
+	if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
+						EXT4_FREEBLOCKS_WATERMARK) {
+		free_blocks  = percpu_counter_sum_positive(fbc);
+		dirty_blocks = percpu_counter_sum_positive(dbc);
+	}
+	if (free_blocks <= (root_blocks + dirty_blocks))
 		/* we don't have free space */
 		return 0;
-	if (free_blocks - root_blocks < nblocks)
+	if (free_blocks - (root_blocks + dirty_blocks) < nblocks)
 		return free_blocks - root_blocks;
 	return nblocks;
 }
@@ -2089,13 +2106,14 @@ allocated:
 	le16_add_cpu(&gdp->bg_free_blocks_count, -num);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
-	if (!EXT4_I(inode)->i_delalloc_reserved_flag && (*count != num)) {
-		/*
-		 * we allocated less blocks than we
-		 * claimed. Add the difference back.
-		 */
-		percpu_counter_add(&sbi->s_freeblocks_counter, *count - num);
-	}
+	percpu_counter_sub(&sbi->s_freeblocks_counter, num);
+	/*
+	 * Now reduce the dirty block count also. Should not go negative
+	 */
+	if (!EXT4_I(inode)->i_delalloc_reserved_flag)
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, *count);
+	else
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, num);
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
 		spin_lock(sb_bgl_lock(sbi, flex_group));
--- a/fs/ext4/ext4_sb.h
+++ b/fs/ext4/ext4_sb.h
@@ -60,6 +60,7 @@ struct ext4_sb_info {
 	struct percpu_counter s_freeblocks_counter;
 	struct percpu_counter s_freeinodes_counter;
 	struct percpu_counter s_dirs_counter;
+	struct percpu_counter s_dirtyblocks_counter;
 	struct blockgroup_lock s_blockgroup_lock;
 
 	/* root of the per fs reservation window tree */
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1032,19 +1032,20 @@ static void ext4_da_update_reserve_space
 	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
 	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
 
-	/* Account for allocated meta_blocks */
-	mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
-
-	/* update fs free blocks counter for truncate case */
-	percpu_counter_add(&sbi->s_freeblocks_counter, mdb_free);
+	if (mdb_free) {
+		/* Account for allocated meta_blocks */
+		mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
+
+		/* update fs dirty blocks counter */
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
+		EXT4_I(inode)->i_allocated_meta_blocks = 0;
+		EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+	}
 
 	/* update per-inode reservations */
 	BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
 	EXT4_I(inode)->i_reserved_data_blocks -= used;
 
-	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
-	EXT4_I(inode)->i_reserved_meta_blocks = mdb;
-	EXT4_I(inode)->i_allocated_meta_blocks = 0;
 	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 
 	/*
@@ -1609,8 +1610,8 @@ static void ext4_da_release_space(struct
 
 	release = to_free + mdb_free;
 
-	/* update fs free blocks counter for truncate case */
-	percpu_counter_add(&sbi->s_freeblocks_counter, release);
+	/* update fs dirty blocks counter for truncate case */
+	percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
 
 	/* update per-inode reservations */
 	BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
@@ -2546,7 +2547,6 @@ static int ext4_da_write_begin(struct fi
 	index = pos >> PAGE_CACHE_SHIFT;
 	from = pos & (PAGE_CACHE_SIZE - 1);
 	to = from + len;
-
 retry:
 	/*
 	 * With delayed allocation, we don't log the i_disksize update
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3100,7 +3100,7 @@ void exit_ext4_mballoc(void)
  */
 static noinline_for_stack int
 ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
-				handle_t *handle)
+				handle_t *handle, unsigned long reserv_blks)
 {
 	struct buffer_head *bitmap_bh = NULL;
 	struct ext4_super_block *es;
@@ -3188,21 +3188,16 @@ ext4_mb_mark_diskspace_used(struct ext4_
 	le16_add_cpu(&gdp->bg_free_blocks_count, -ac->ac_b_ex.fe_len);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
 	spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
-
+	percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
 	/*
-	 * free blocks account has already be reduced/reserved
-	 * at write_begin() time for delayed allocation
-	 * do not double accounting
+	 * Now reduce the dirty block count also. Should not go negative
 	 */
-	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED) &&
-			ac->ac_o_ex.fe_len != ac->ac_b_ex.fe_len) {
-		/*
-		 * we allocated less blocks than we calimed
-		 * Add the difference back
-		 */
-		percpu_counter_add(&sbi->s_freeblocks_counter,
-				ac->ac_o_ex.fe_len - ac->ac_b_ex.fe_len);
-	}
+	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
+		/* release all the reserved blocks if non delalloc */
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter, reserv_blks);
+	else
+		percpu_counter_sub(&sbi->s_dirtyblocks_counter,
+						ac->ac_b_ex.fe_len);
 
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi,
@@ -4636,12 +4631,13 @@ static int ext4_mb_discard_preallocation
 ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 				 struct ext4_allocation_request *ar, int *errp)
 {
+	int freed;
 	struct ext4_allocation_context *ac = NULL;
 	struct ext4_sb_info *sbi;
 	struct super_block *sb;
 	ext4_fsblk_t block = 0;
-	int freed;
-	int inquota;
+	unsigned long inquota;
+	unsigned long reserv_blks = 0;
 
 	sb = ar->inode->i_sb;
 	sbi = EXT4_SB(sb);
@@ -4659,6 +4655,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
 			*errp = -ENOSPC;
 			return 0;
 		}
+		reserv_blks = ar->len;
 	}
 	while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) {
 		ar->flags |= EXT4_MB_HINT_NOPREALLOC;
@@ -4704,7 +4701,7 @@ repeat:
 			ext4_mb_new_preallocation(ac);
 	}
 	if (likely(ac->ac_status == AC_STATUS_FOUND)) {
-		*errp = ext4_mb_mark_diskspace_used(ac, handle);
+		*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_blks);
 		if (*errp ==  -EAGAIN) {
 			/*
 			 * drop the reference that we took
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -521,6 +521,7 @@ static void ext4_put_super(struct super_
 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
 	percpu_counter_destroy(&sbi->s_dirs_counter);
+	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 	brelse(sbi->s_sbh);
 #ifdef CONFIG_QUOTA
 	for (i = 0; i < MAXQUOTAS; i++)
@@ -2280,6 +2281,9 @@ static int ext4_fill_super(struct super_
 		err = percpu_counter_init(&sbi->s_dirs_counter,
 				ext4_count_dirs(sb));
 	}
+	if (!err) {
+		err = percpu_counter_init(&sbi->s_dirtyblocks_counter, 0);
+	}
 	if (err) {
 		printk(KERN_ERR "EXT4-fs: insufficient memory\n");
 		goto failed_mount3;
@@ -2517,6 +2521,7 @@ failed_mount3:
 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
 	percpu_counter_destroy(&sbi->s_dirs_counter);
+	percpu_counter_destroy(&sbi->s_dirtyblocks_counter);
 failed_mount2:
 	for (i = 0; i < db_count; i++)
 		brelse(sbi->s_group_desc[i]);
@@ -3208,7 +3213,8 @@ static int ext4_statfs(struct dentry *de
 	buf->f_type = EXT4_SUPER_MAGIC;
 	buf->f_bsize = sb->s_blocksize;
 	buf->f_blocks = ext4_blocks_count(es) - sbi->s_overhead_last;
-	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
+	buf->f_bfree = percpu_counter_sum_positive(&sbi->s_freeblocks_counter) -
+		       percpu_counter_sum_positive(&sbi->s_dirtyblocks_counter);
 	ext4_free_blocks_count_set(es, buf->f_bfree);
 	buf->f_bavail = buf->f_bfree - ext4_r_blocks_count(es);
 	if (buf->f_bfree < ext4_r_blocks_count(es))


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch ext4-fix-file-fragmentation-during-large-file-write.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: Fix file fragmentation during large file write.

to the 2.6.27-stable tree.  Its filename is

    ext4-fix-file-fragmentation-during-large-file-write.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:23:42 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:26:04 -0400
Subject: ext4: Fix file fragmentation during large file write.
To: stable@kernel.org
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>, "Theodore Ts'o" <tytso@mit.edu>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-11-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 22208dedbd7626e5fc4339c417f8d24cc21f79d7 upstream.

The range_cyclic writeback mode uses the address_space writeback_index
as the start index for writeback.  With delayed allocation we were
updating writeback_index wrongly resulting in highly fragmented file.
This patch reduces the number of extents reduced from 4000 to 27 for a
3GB file.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[dev@jaysonking.com: Some changed lines from the original version of this patch were dropped, since they were rolled up with another cherry-picked patch applied to 2.6.27.y earlier.]
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ext4/inode.c |   88 +++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 55 insertions(+), 33 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1721,7 +1721,11 @@ static int mpage_da_submit_io(struct mpa
 
 			pages_skipped = mpd->wbc->pages_skipped;
 			err = mapping->a_ops->writepage(page, mpd->wbc);
-			if (!err)
+			if (!err && (pages_skipped == mpd->wbc->pages_skipped))
+				/*
+				 * have successfully written the page
+				 * without skipping the same
+				 */
 				mpd->pages_written++;
 			/*
 			 * In error case, we have to continue because
@@ -2175,7 +2179,6 @@ static int mpage_da_writepages(struct ad
 			       struct writeback_control *wbc,
 			       struct mpage_da_data *mpd)
 {
-	long to_write;
 	int ret;
 
 	if (!mpd->get_block)
@@ -2190,19 +2193,18 @@ static int mpage_da_writepages(struct ad
 	mpd->pages_written = 0;
 	mpd->retval = 0;
 
-	to_write = wbc->nr_to_write;
-
 	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);
-
 	/*
 	 * Handle last extent of pages
 	 */
 	if (!mpd->io_done && mpd->next_page != mpd->first_page) {
 		if (mpage_da_map_blocks(mpd) == 0)
 			mpage_da_submit_io(mpd);
-	}
 
-	wbc->nr_to_write = to_write - mpd->pages_written;
+		mpd->io_done = 1;
+		ret = MPAGE_DA_EXTENT_TAIL;
+	}
+	wbc->nr_to_write -= mpd->pages_written;
 	return ret;
 }
 
@@ -2447,11 +2449,14 @@ static int ext4_da_writepages_trans_bloc
 static int ext4_da_writepages(struct address_space *mapping,
 			      struct writeback_control *wbc)
 {
+	pgoff_t	index;
+	int range_whole = 0;
 	handle_t *handle = NULL;
 	struct mpage_da_data mpd;
 	struct inode *inode = mapping->host;
+	int no_nrwrite_index_update;
+	long pages_written = 0, pages_skipped;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
-	long to_write, pages_skipped = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
 
 	/*
@@ -2485,16 +2490,26 @@ static int ext4_da_writepages(struct add
 		nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
 		wbc->nr_to_write = sbi->s_mb_stream_request;
 	}
+	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
+		range_whole = 1;
 
-
-	pages_skipped = wbc->pages_skipped;
+	if (wbc->range_cyclic)
+		index = mapping->writeback_index;
+	else
+		index = wbc->range_start >> PAGE_CACHE_SHIFT;
 
 	mpd.wbc = wbc;
 	mpd.inode = mapping->host;
 
-restart_loop:
-	to_write = wbc->nr_to_write;
-	while (!ret && to_write > 0) {
+	/*
+	 * we don't want write_cache_pages to update
+	 * nr_to_write and writeback_index
+	 */
+	no_nrwrite_index_update = wbc->no_nrwrite_index_update;
+	wbc->no_nrwrite_index_update = 1;
+	pages_skipped = wbc->pages_skipped;
+
+	while (!ret && wbc->nr_to_write > 0) {
 
 		/*
 		 * we  insert one extent at a time. So we need
@@ -2527,46 +2542,53 @@ restart_loop:
 				goto out_writepages;
 			}
 		}
-		to_write -= wbc->nr_to_write;
-
 		mpd.get_block = ext4_da_get_block_write;
 		ret = mpage_da_writepages(mapping, wbc, &mpd);
 
 		ext4_journal_stop(handle);
 
-		if (mpd.retval == -ENOSPC)
+		if (mpd.retval == -ENOSPC) {
+			/* commit the transaction which would
+			 * free blocks released in the transaction
+			 * and try again
+			 */
 			jbd2_journal_force_commit_nested(sbi->s_journal);
-
-		/* reset the retry count */
-		if (ret == MPAGE_DA_EXTENT_TAIL) {
+			wbc->pages_skipped = pages_skipped;
+			ret = 0;
+		} else if (ret == MPAGE_DA_EXTENT_TAIL) {
 			/*
 			 * got one extent now try with
 			 * rest of the pages
 			 */
-			to_write += wbc->nr_to_write;
+			pages_written += mpd.pages_written;
+			wbc->pages_skipped = pages_skipped;
 			ret = 0;
-		} else if (wbc->nr_to_write) {
+		} else if (wbc->nr_to_write)
 			/*
 			 * There is no more writeout needed
 			 * or we requested for a noblocking writeout
 			 * and we found the device congested
 			 */
-			to_write += wbc->nr_to_write;
 			break;
-		}
-		wbc->nr_to_write = to_write;
-	}
-
-	if (!wbc->range_cyclic && (pages_skipped != wbc->pages_skipped)) {
-		/* We skipped pages in this loop */
-		wbc->nr_to_write = to_write +
-				wbc->pages_skipped - pages_skipped;
-		wbc->pages_skipped = pages_skipped;
-		goto restart_loop;
 	}
+	if (pages_skipped != wbc->pages_skipped)
+		printk(KERN_EMERG "This should not happen leaving %s "
+				"with nr_to_write = %ld ret = %d\n",
+				__func__, wbc->nr_to_write, ret);
+
+	/* Update index */
+	index += pages_written;
+	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+		/*
+		 * set the writeback_index so that range_cyclic
+		 * mode will write it back later
+		 */
+		mapping->writeback_index = index;
 
 out_writepages:
-	wbc->nr_to_write = to_write - nr_to_writebump;
+	if (!no_nrwrite_index_update)
+		wbc->no_nrwrite_index_update = 0;
+	wbc->nr_to_write -= nr_to_writebump;
 	return ret;
 }
 


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: Implement range_cyclic in ext4_da_writepages instead of write_cache_pages

to the 2.6.27-stable tree.  Its filename is

    ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:24:03 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:26:05 -0400
Subject: ext4: Implement range_cyclic in ext4_da_writepages instead of write_cache_pages
To: stable@kernel.org
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>, "Theodore Ts'o" <tytso@mit.edu>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-12-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 2acf2c261b823d9d9ed954f348b97620297a36b5 upstream.

With delayed allocation we lock the page in write_cache_pages() and
try to build an in memory extent of contiguous blocks.  This is needed
so that we can get large contiguous blocks request.  If range_cyclic
mode is enabled, write_cache_pages() will loop back to the 0 index if
no I/O has been done yet, and try to start writing from the beginning
of the range.  That causes an attempt to take the page lock of lower
index page while holding the page lock of higher index page, which can
cause a dead lock with another writeback thread.

The solution is to implement the range_cyclic behavior in
ext4_da_writepages() instead.

http://bugzilla.kernel.org/show_bug.cgi?id=12579

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ext4/inode.c |   21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2456,6 +2456,7 @@ static int ext4_da_writepages(struct add
 	struct inode *inode = mapping->host;
 	int no_nrwrite_index_update;
 	long pages_written = 0, pages_skipped;
+	int range_cyclic, cycled = 1, io_done = 0;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
 	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
 
@@ -2493,9 +2494,15 @@ static int ext4_da_writepages(struct add
 	if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 		range_whole = 1;
 
-	if (wbc->range_cyclic)
+	range_cyclic = wbc->range_cyclic;
+	if (wbc->range_cyclic) {
 		index = mapping->writeback_index;
-	else
+		if (index)
+			cycled = 0;
+		wbc->range_start = index << PAGE_CACHE_SHIFT;
+		wbc->range_end  = LLONG_MAX;
+		wbc->range_cyclic = 0;
+	} else
 		index = wbc->range_start >> PAGE_CACHE_SHIFT;
 
 	mpd.wbc = wbc;
@@ -2509,6 +2516,7 @@ static int ext4_da_writepages(struct add
 	wbc->no_nrwrite_index_update = 1;
 	pages_skipped = wbc->pages_skipped;
 
+retry:
 	while (!ret && wbc->nr_to_write > 0) {
 
 		/*
@@ -2563,6 +2571,7 @@ static int ext4_da_writepages(struct add
 			pages_written += mpd.pages_written;
 			wbc->pages_skipped = pages_skipped;
 			ret = 0;
+			io_done = 1;
 		} else if (wbc->nr_to_write)
 			/*
 			 * There is no more writeout needed
@@ -2571,6 +2580,13 @@ static int ext4_da_writepages(struct add
 			 */
 			break;
 	}
+	if (!io_done && !cycled) {
+		cycled = 1;
+		index = 0;
+		wbc->range_start = index << PAGE_CACHE_SHIFT;
+		wbc->range_end  = mapping->writeback_index - 1;
+		goto retry;
+	}
 	if (pages_skipped != wbc->pages_skipped)
 		printk(KERN_EMERG "This should not happen leaving %s "
 				"with nr_to_write = %ld ret = %d\n",
@@ -2578,6 +2594,7 @@ static int ext4_da_writepages(struct add
 
 	/* Update index */
 	index += pages_written;
+	wbc->range_cyclic = range_cyclic;
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		/*
 		 * set the writeback_index so that range_cyclic


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: invalidate pages if delalloc block allocation fails.

to the 2.6.27-stable tree.  Its filename is

    ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:19:40 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:25:55 -0400
Subject: ext4: invalidate pages if delalloc block allocation fails.
To: stable@kernel.org
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>, "Theodore Ts'o" <tytso@mit.edu>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-2-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit c4a0c46ec92c194c873232b88debce4e1a448483 upstream.

We are a bit agressive in invalidating all the pages. But
it is ok because we really don't know why the block allocation
failed and it is better to come of the writeback path
so that user can look for more info.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ext4/inode.c |   85 ++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 73 insertions(+), 12 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1821,6 +1821,39 @@ static inline void __unmap_underlying_bl
 		unmap_underlying_metadata(bdev, bh->b_blocknr + i);
 }
 
+static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
+					sector_t logical, long blk_cnt)
+{
+	int nr_pages, i;
+	pgoff_t index, end;
+	struct pagevec pvec;
+	struct inode *inode = mpd->inode;
+	struct address_space *mapping = inode->i_mapping;
+
+	index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
+	end   = (logical + blk_cnt - 1) >>
+				(PAGE_CACHE_SHIFT - inode->i_blkbits);
+	while (index <= end) {
+		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+		if (nr_pages == 0)
+			break;
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+			index = page->index;
+			if (index > end)
+				break;
+			index++;
+
+			BUG_ON(!PageLocked(page));
+			BUG_ON(PageWriteback(page));
+			block_invalidatepage(page, 0);
+			ClearPageUptodate(page);
+			unlock_page(page);
+		}
+	}
+	return;
+}
+
 /*
  * mpage_da_map_blocks - go through given space
  *
@@ -1830,7 +1863,7 @@ static inline void __unmap_underlying_bl
  * The function skips space we know is already mapped to disk blocks.
  *
  */
-static void mpage_da_map_blocks(struct mpage_da_data *mpd)
+static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 {
 	int err = 0;
 	struct buffer_head *lbh = &mpd->lbh;
@@ -1841,7 +1874,7 @@ static void mpage_da_map_blocks(struct m
 	 * We consider only non-mapped and non-allocated blocks
 	 */
 	if (buffer_mapped(lbh) && !buffer_delay(lbh))
-		return;
+		return 0;
 
 	new.b_state = lbh->b_state;
 	new.b_blocknr = 0;
@@ -1852,10 +1885,38 @@ static void mpage_da_map_blocks(struct m
 	 * to write simply return
 	 */
 	if (!new.b_size)
-		return;
+		return 0;
 	err = mpd->get_block(mpd->inode, next, &new, 1);
-	if (err)
-		return;
+	if (err) {
+
+		/* If get block returns with error
+		 * we simply return. Later writepage
+		 * will redirty the page and writepages
+		 * will find the dirty page again
+		 */
+		if (err == -EAGAIN)
+			return 0;
+		/*
+		 * get block failure will cause us
+		 * to loop in writepages. Because
+		 * a_ops->writepage won't be able to
+		 * make progress. The page will be redirtied
+		 * by writepage and writepages will again
+		 * try to write the same.
+		 */
+		printk(KERN_EMERG "%s block allocation failed for inode %lu "
+				  "at logical offset %llu with max blocks "
+				  "%zd with error %d\n",
+				  __func__, mpd->inode->i_ino,
+				  (unsigned long long)next,
+				  lbh->b_size >> mpd->inode->i_blkbits, err);
+		printk(KERN_EMERG "This should not happen.!! "
+					"Data will be lost\n");
+		/* invlaidate all the pages */
+		ext4_da_block_invalidatepages(mpd, next,
+				lbh->b_size >> mpd->inode->i_blkbits);
+		return err;
+	}
 	BUG_ON(new.b_size == 0);
 
 	if (buffer_new(&new))
@@ -1868,7 +1929,7 @@ static void mpage_da_map_blocks(struct m
 	if (buffer_delay(lbh) || buffer_unwritten(lbh))
 		mpage_put_bnr_to_bhs(mpd, next, &new);
 
-	return;
+	return 0;
 }
 
 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
@@ -1937,8 +1998,8 @@ flush_it:
 	 * We couldn't merge the block to our extent, so we
 	 * need to flush current  extent and start new one
 	 */
-	mpage_da_map_blocks(mpd);
-	mpage_da_submit_io(mpd);
+	if (mpage_da_map_blocks(mpd) == 0)
+		mpage_da_submit_io(mpd);
 	mpd->io_done = 1;
 	return;
 }
@@ -1980,8 +2041,8 @@ static int __mpage_da_writepage(struct p
 		 * and start IO on them using writepage()
 		 */
 		if (mpd->next_page != mpd->first_page) {
-			mpage_da_map_blocks(mpd);
-			mpage_da_submit_io(mpd);
+			if (mpage_da_map_blocks(mpd) == 0)
+				mpage_da_submit_io(mpd);
 			/*
 			 * skip rest of the page in the page_vec
 			 */
@@ -2102,8 +2163,8 @@ static int mpage_da_writepages(struct ad
 	 * Handle last extent of pages
 	 */
 	if (!mpd.io_done && mpd.next_page != mpd.first_page) {
-		mpage_da_map_blocks(&mpd);
-		mpage_da_submit_io(&mpd);
+		if (mpage_da_map_blocks(&mpd) == 0)
+			mpage_da_submit_io(&mpd);
 	}
 
 	wbc->nr_to_write = to_write - mpd.pages_written;


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: Make sure all the block allocation paths reserve blocks

to the 2.6.27-stable tree.  Its filename is

    ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:20:41 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:25:57 -0400
Subject: ext4: Make sure all the block allocation paths reserve blocks
To: stable@kernel.org
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>, "Theodore Ts'o" <tytso@mit.edu>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-4-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit a30d542a0035b886ffaafd0057ced0a2b28c3a4f upstream.

With delayed allocation we need to make sure block are reserved before
we attempt to allocate them. Otherwise we get block allocation failure
(ENOSPC) during writepages which cannot be handled. This would mean
silent data loss (We do a printk stating data will be lost). This patch
updates the DIO and fallocate code path to do block reservation before
block allocation. This is needed to make sure parallel DIO and fallocate
request doesn't take block out of delayed reserve space.

When free blocks count go below a threshold we switch to a slow patch
which looks at other CPU's accumulated percpu counter values.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ext4/balloc.c  |   58 +++++++++++++++++++++++++++++++++++++++---------------
 fs/ext4/ext4.h    |   13 ++++++++++++
 fs/ext4/inode.c   |    5 ----
 fs/ext4/mballoc.c |   23 ++++++++++++---------
 4 files changed, 69 insertions(+), 30 deletions(-)

--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1754,6 +1754,32 @@ out:
 	return ret;
 }
 
+int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
+						ext4_fsblk_t nblocks)
+{
+	s64 free_blocks;
+	ext4_fsblk_t root_blocks = 0;
+	struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
+
+	free_blocks = percpu_counter_read(fbc);
+
+	if (!capable(CAP_SYS_RESOURCE) &&
+		sbi->s_resuid != current->fsuid &&
+		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
+		root_blocks = ext4_r_blocks_count(sbi->s_es);
+
+	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
+		free_blocks = percpu_counter_sum(&sbi->s_freeblocks_counter);
+
+	if (free_blocks < (root_blocks + nblocks))
+		/* we don't have free space */
+		return -ENOSPC;
+
+	/* reduce fs free blocks counter */
+	percpu_counter_sub(fbc, nblocks);
+	return 0;
+}
+
 /**
  * ext4_has_free_blocks()
  * @sbi:	in-core super block structure.
@@ -1775,18 +1801,17 @@ ext4_fsblk_t ext4_has_free_blocks(struct
 		sbi->s_resuid != current->fsuid &&
 		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
 		root_blocks = ext4_r_blocks_count(sbi->s_es);
-#ifdef CONFIG_SMP
-	if (free_blocks - root_blocks < FBC_BATCH)
-		free_blocks =
-			percpu_counter_sum(&sbi->s_freeblocks_counter);
-#endif
+
+	if (free_blocks - (nblocks + root_blocks) < EXT4_FREEBLOCKS_WATERMARK)
+		free_blocks = percpu_counter_sum_positive(&sbi->s_freeblocks_counter);
+
 	if (free_blocks <= root_blocks)
 		/* we don't have free space */
 		return 0;
 	if (free_blocks - root_blocks < nblocks)
 		return free_blocks - root_blocks;
 	return nblocks;
- }
+}
 
 
 /**
@@ -1865,14 +1890,11 @@ ext4_fsblk_t ext4_old_new_blocks(handle_
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		*count = ext4_has_free_blocks(sbi, *count);
-	}
-	if (*count == 0) {
-		*errp = -ENOSPC;
-		return 0;	/*return with ENOSPC error */
+		if (ext4_claim_free_blocks(sbi, *count)) {
+			*errp = -ENOSPC;
+			return 0;	/*return with ENOSPC error */
+		}
 	}
-	num = *count;
-
 	/*
 	 * Check quota for allocation of this block.
 	 */
@@ -2067,9 +2089,13 @@ allocated:
 	le16_add_cpu(&gdp->bg_free_blocks_count, -num);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
-	if (!EXT4_I(inode)->i_delalloc_reserved_flag)
-		percpu_counter_sub(&sbi->s_freeblocks_counter, num);
-
+	if (!EXT4_I(inode)->i_delalloc_reserved_flag && (*count != num)) {
+		/*
+		 * we allocated less blocks than we
+		 * claimed. Add the difference back.
+		 */
+		percpu_counter_add(&sbi->s_freeblocks_counter, *count - num);
+	}
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
 		spin_lock(sb_bgl_lock(sbi, flex_group));
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1015,6 +1015,8 @@ extern ext4_fsblk_t ext4_new_blocks(hand
 					unsigned long *count, int *errp);
 extern ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t goal, unsigned long *count, int *errp);
+extern int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
+						ext4_fsblk_t nblocks);
 extern ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
 						ext4_fsblk_t nblocks);
 extern void ext4_free_blocks (handle_t *handle, struct inode *inode,
@@ -1245,6 +1247,17 @@ do {								\
 		__ext4_std_error((sb), __func__, (errno));	\
 } while (0)
 
+#ifdef CONFIG_SMP
+/* Each CPU can accumulate FBC_BATCH blocks in their local
+ * counters. So we need to make sure we have free blocks more
+ * than FBC_BATCH  * nr_cpu_ids. Also add a window of 4 times.
+ */
+#define EXT4_FREEBLOCKS_WATERMARK (4 * (FBC_BATCH * nr_cpu_ids))
+#else
+#define EXT4_FREEBLOCKS_WATERMARK 0
+#endif
+
+
 /*
  * Inodes and files operations
  */
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1564,13 +1564,10 @@ static int ext4_da_reserve_space(struct
 	md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
 	total = md_needed + nrblocks;
 
-	if (ext4_has_free_blocks(sbi, total) < total) {
+	if (ext4_claim_free_blocks(sbi, total)) {
 		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 		return -ENOSPC;
 	}
-	/* reduce fs free blocks counter */
-	percpu_counter_sub(&sbi->s_freeblocks_counter, total);
-
 	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
 	EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
 
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3194,9 +3194,15 @@ ext4_mb_mark_diskspace_used(struct ext4_
 	 * at write_begin() time for delayed allocation
 	 * do not double accounting
 	 */
-	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
-		percpu_counter_sub(&sbi->s_freeblocks_counter,
-					ac->ac_b_ex.fe_len);
+	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED) &&
+			ac->ac_o_ex.fe_len != ac->ac_b_ex.fe_len) {
+		/*
+		 * we allocated less blocks than we calimed
+		 * Add the difference back
+		 */
+		percpu_counter_add(&sbi->s_freeblocks_counter,
+				ac->ac_o_ex.fe_len - ac->ac_b_ex.fe_len);
+	}
 
 	if (sbi->s_log_groups_per_flex) {
 		ext4_group_t flex_group = ext4_flex_group(sbi,
@@ -4649,14 +4655,11 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		ar->len = ext4_has_free_blocks(sbi, ar->len);
-	}
-
-	if (ar->len == 0) {
-		*errp = -ENOSPC;
-		return 0;
+		if (ext4_claim_free_blocks(sbi, ar->len)) {
+			*errp = -ENOSPC;
+			return 0;
+		}
 	}

patch ext4-retry-block-allocation-if-we-have-free-blocks-left.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: Retry block allocation if we have free blocks left

to the 2.6.27-stable tree.  Its filename is

    ext4-retry-block-allocation-if-we-have-free-blocks-left.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:22:08 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:26:00 -0400
Subject: ext4: Retry block allocation if we have free blocks left
To: stable@kernel.org
Cc: "Theodore Ts'o" <tytso@mit.edu>, Ext4 Developers List <linux-ext4@vger.kernel.org>, Mingming Cao <cmm@us.ibm.com>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-7-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit df22291ff0fde0d350cf15dac3e5cc33ac528875 upstream.

When we truncate files, the meta-data blocks released are not reused
untill we commit the truncate transaction.  That means delayed get_block
request will return ENOSPC even if we have free blocks left.  Force a
journal commit and retry block allocation if we get ENOSPC with free
blocks left.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ext4/inode.c |   81 +++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 57 insertions(+), 24 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1661,6 +1661,7 @@ struct mpage_da_data {
 	struct writeback_control *wbc;
 	int io_done;
 	long pages_written;
+	int retval;
 };
 
 /*
@@ -1858,6 +1859,24 @@ static void ext4_da_block_invalidatepage
 	return;
 }
 
+static void ext4_print_free_blocks(struct inode *inode)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	printk(KERN_EMERG "Total free blocks count %lld\n",
+			ext4_count_free_blocks(inode->i_sb));
+	printk(KERN_EMERG "Free/Dirty block details\n");
+	printk(KERN_EMERG "free_blocks=%lld\n",
+			percpu_counter_sum(&sbi->s_freeblocks_counter));
+	printk(KERN_EMERG "dirty_blocks=%lld\n",
+			percpu_counter_sum(&sbi->s_dirtyblocks_counter));
+	printk(KERN_EMERG "Block reservation details\n");
+	printk(KERN_EMERG "i_reserved_data_blocks=%lu\n",
+			EXT4_I(inode)->i_reserved_data_blocks);
+	printk(KERN_EMERG "i_reserved_meta_blocks=%lu\n",
+			EXT4_I(inode)->i_reserved_meta_blocks);
+	return;
+}
+
 /*
  * mpage_da_map_blocks - go through given space
  *
@@ -1872,7 +1891,7 @@ static int  mpage_da_map_blocks(struct m
 	int err = 0;
 	struct buffer_head new;
 	struct buffer_head *lbh = &mpd->lbh;
-	sector_t next = lbh->b_blocknr;
+	sector_t next;
 
 	/*
 	 * We consider only non-mapped and non-allocated blocks
@@ -1882,6 +1901,7 @@ static int  mpage_da_map_blocks(struct m
 	new.b_state = lbh->b_state;
 	new.b_blocknr = 0;
 	new.b_size = lbh->b_size;
+	next = lbh->b_blocknr;
 	/*
 	 * If we didn't accumulate anything
 	 * to write simply return
@@ -1898,6 +1918,13 @@ static int  mpage_da_map_blocks(struct m
 		 */
 		if (err == -EAGAIN)
 			return 0;
+
+		if (err == -ENOSPC &&
+				ext4_count_free_blocks(mpd->inode->i_sb)) {
+			mpd->retval = err;
+			return 0;
+		}
+
 		/*
 		 * get block failure will cause us
 		 * to loop in writepages. Because
@@ -1915,8 +1942,7 @@ static int  mpage_da_map_blocks(struct m
 		printk(KERN_EMERG "This should not happen.!! "
 					"Data will be lost\n");
 		if (err == -ENOSPC) {
-			printk(KERN_CRIT "Total free blocks count %lld\n",
-				ext4_count_free_blocks(mpd->inode->i_sb));
+			ext4_print_free_blocks(mpd->inode);
 		}
 		/* invlaidate all the pages */
 		ext4_da_block_invalidatepages(mpd, next,
@@ -2141,39 +2167,36 @@ static int __mpage_da_writepage(struct p
  */
 static int mpage_da_writepages(struct address_space *mapping,
 			       struct writeback_control *wbc,
-			       get_block_t get_block)
+			       struct mpage_da_data *mpd)
 {
-	struct mpage_da_data mpd;
 	long to_write;
 	int ret;
 
-	if (!get_block)
+	if (!mpd->get_block)
 		return generic_writepages(mapping, wbc);
 
-	mpd.wbc = wbc;
-	mpd.inode = mapping->host;
-	mpd.lbh.b_size = 0;
-	mpd.lbh.b_state = 0;
-	mpd.lbh.b_blocknr = 0;
-	mpd.first_page = 0;
-	mpd.next_page = 0;
-	mpd.get_block = get_block;
-	mpd.io_done = 0;
-	mpd.pages_written = 0;
+	mpd->lbh.b_size = 0;
+	mpd->lbh.b_state = 0;
+	mpd->lbh.b_blocknr = 0;
+	mpd->first_page = 0;
+	mpd->next_page = 0;
+	mpd->io_done = 0;
+	mpd->pages_written = 0;
+	mpd->retval = 0;
 
 	to_write = wbc->nr_to_write;
 
-	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, &mpd);
+	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, mpd);
 
 	/*
 	 * Handle last extent of pages
 	 */
-	if (!mpd.io_done && mpd.next_page != mpd.first_page) {
-		if (mpage_da_map_blocks(&mpd) == 0)
-			mpage_da_submit_io(&mpd);
+	if (!mpd->io_done && mpd->next_page != mpd->first_page) {
+		if (mpage_da_map_blocks(mpd) == 0)
+			mpage_da_submit_io(mpd);
 	}
 
-	wbc->nr_to_write = to_write - mpd.pages_written;
+	wbc->nr_to_write = to_write - mpd->pages_written;
 	return ret;
 }
 
@@ -2420,6 +2443,7 @@ static int ext4_da_writepages(struct add
 {
 	handle_t *handle = NULL;
 	loff_t range_start = 0;
+	struct mpage_da_data mpd;
 	struct inode *inode = mapping->host;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
 	long to_write, pages_skipped = 0;
@@ -2467,6 +2491,9 @@ static int ext4_da_writepages(struct add
 	range_start =  wbc->range_start;
 	pages_skipped = wbc->pages_skipped;
 
+	mpd.wbc = wbc;
+	mpd.inode = mapping->host;
+
 restart_loop:
 	to_write = wbc->nr_to_write;
 	while (!ret && to_write > 0) {
@@ -2502,11 +2529,17 @@ restart_loop:
 				goto out_writepages;
 			}
 		}
-
 		to_write -= wbc->nr_to_write;
-		ret = mpage_da_writepages(mapping, wbc,
-					  ext4_da_get_block_write);
+
+		mpd.get_block = ext4_da_get_block_write;
+		ret = mpage_da_writepages(mapping, wbc, &mpd);
+
 		ext4_journal_stop(handle);
+
+		if (mpd.retval == -ENOSPC)
+			jbd2_journal_force_commit_nested(sbi->s_journal);
+
+		/* reset the retry count */
 		if (ret == MPAGE_DA_EXTENT_TAIL) {
 			/*
 			 * got one extent now try with


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch ext4-retry-block-reservation.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: Retry block reservation

to the 2.6.27-stable tree.  Its filename is

    ext4-retry-block-reservation.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:21:18 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:25:59 -0400
Subject: ext4: Retry block reservation
To: stable@kernel.org
Cc: "Theodore Ts'o" <tytso@mit.edu>, Ext4 Developers List <linux-ext4@vger.kernel.org>, Mingming Cao <cmm@us.ibm.com>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-6-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 030ba6bc67b4f2bc5cd174f57785a1745c929abe upstream.

During block reservation if we don't have enough blocks left, retry
block reservation with smaller block counts.  This makes sure we try
fallocate and DIO with smaller request size and don't fail early.  The
delayed allocation reservation cannot try with smaller block count. So
retry block reservation to handle temporary disk full conditions.  Also
print free blocks details if we fail block allocation during writepages.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ext4/balloc.c  |    8 +++++++-
 fs/ext4/inode.c   |   14 +++++++++++---
 fs/ext4/mballoc.c |    7 ++++++-
 3 files changed, 24 insertions(+), 5 deletions(-)

--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1907,10 +1907,16 @@ ext4_fsblk_t ext4_old_new_blocks(handle_
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		if (ext4_claim_free_blocks(sbi, *count)) {
+		while (*count && ext4_claim_free_blocks(sbi, *count)) {
+			/* let others to free the space */
+			yield();
+			*count = *count >> 1;
+		}
+		if (!*count) {
 			*errp = -ENOSPC;
 			return 0;	/*return with ENOSPC error */
 		}
+		num = *count;
 	}
 	/*
 	 * Check quota for allocation of this block.
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1549,6 +1549,7 @@ static int ext4_journalled_write_end(str
 
 static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
 {
+	int retries = 0;
        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
        unsigned long md_needed, mdblocks, total = 0;
 
@@ -1557,6 +1558,7 @@ static int ext4_da_reserve_space(struct
 	 * in order to allocate nrblocks
 	 * worse case is one extent per block
 	 */
+repeat:
 	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
 	total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
 	mdblocks = ext4_calc_metadata_amount(inode, total);
@@ -1567,6 +1569,10 @@ static int ext4_da_reserve_space(struct
 
 	if (ext4_claim_free_blocks(sbi, total)) {
 		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+		if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
+			yield();
+			goto repeat;
+		}
 		return -ENOSPC;
 	}
 	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
@@ -1864,20 +1870,18 @@ static void ext4_da_block_invalidatepage
 static int  mpage_da_map_blocks(struct mpage_da_data *mpd)
 {
 	int err = 0;
+	struct buffer_head new;
 	struct buffer_head *lbh = &mpd->lbh;
 	sector_t next = lbh->b_blocknr;
-	struct buffer_head new;
 
 	/*
 	 * We consider only non-mapped and non-allocated blocks
 	 */
 	if (buffer_mapped(lbh) && !buffer_delay(lbh))
 		return 0;
-
 	new.b_state = lbh->b_state;
 	new.b_blocknr = 0;
 	new.b_size = lbh->b_size;
-
 	/*
 	 * If we didn't accumulate anything
 	 * to write simply return
@@ -1910,6 +1914,10 @@ static int  mpage_da_map_blocks(struct m
 				  lbh->b_size >> mpd->inode->i_blkbits, err);
 		printk(KERN_EMERG "This should not happen.!! "
 					"Data will be lost\n");
+		if (err == -ENOSPC) {
+			printk(KERN_CRIT "Total free blocks count %lld\n",
+				ext4_count_free_blocks(mpd->inode->i_sb));
+		}
 		/* invlaidate all the pages */
 		ext4_da_block_invalidatepages(mpd, next,
 				lbh->b_size >> mpd->inode->i_blkbits);
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4651,7 +4651,12 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t
 		/*
 		 * With delalloc we already reserved the blocks
 		 */
-		if (ext4_claim_free_blocks(sbi, ar->len)) {
+		while (ar->len && ext4_claim_free_blocks(sbi, ar->len)) {
+			/* let others to free the space */
+			yield();
+			ar->len = ar->len >> 1;
+		}
+		if (!ar->len) {
 			*errp = -ENOSPC;
 			return 0;
 		}


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: ext4: Use tag dirty lookup during mpage_da_submit_io

to the 2.6.27-stable tree.  Its filename is

    ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:22:28 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:26:01 -0400
Subject: ext4: Use tag dirty lookup during mpage_da_submit_io
To: stable@kernel.org
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>, "Theodore Ts'o" <tytso@mit.edu>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-8-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit af6f029d3836eb7264cd3fbb13a6baf0e5fdb5ea upstream.

This enables us to drop the range_cont writeback mode
use from ext4_da_writepages.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 fs/ext4/inode.c |   30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1699,17 +1699,23 @@ static int mpage_da_submit_io(struct mpa
 
 	pagevec_init(&pvec, 0);
 	while (index <= end) {
-		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+		/*
+		 * We can use PAGECACHE_TAG_DIRTY lookup here because
+		 * even though we have cleared the dirty flag on the page
+		 * We still keep the page in the radix tree with tag
+		 * PAGECACHE_TAG_DIRTY. See clear_page_dirty_for_io.
+		 * The PAGECACHE_TAG_DIRTY is cleared in set_page_writeback
+		 * which is called via the below writepage callback.
+		 */
+		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+					PAGECACHE_TAG_DIRTY,
+					min(end - index,
+					(pgoff_t)PAGEVEC_SIZE-1) + 1);
 		if (nr_pages == 0)
 			break;
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pvec.pages[i];
 
-			index = page->index;
-			if (index > end)
-				break;
-			index++;
-
 			BUG_ON(!PageLocked(page));
 			BUG_ON(PageWriteback(page));
 
@@ -2442,7 +2448,6 @@ static int ext4_da_writepages(struct add
 			      struct writeback_control *wbc)
 {
 	handle_t *handle = NULL;
-	loff_t range_start = 0;
 	struct mpage_da_data mpd;
 	struct inode *inode = mapping->host;
 	int needed_blocks, ret = 0, nr_to_writebump = 0;
@@ -2481,14 +2486,7 @@ static int ext4_da_writepages(struct add
 		wbc->nr_to_write = sbi->s_mb_stream_request;
 	}
 
-	if (!wbc->range_cyclic)
-		/*
-		 * If range_cyclic is not set force range_cont
-		 * and save the old writeback_index
-		 */
-		wbc->range_cont = 1;
 
-	range_start =  wbc->range_start;
 	pages_skipped = wbc->pages_skipped;
 
 	mpd.wbc = wbc;
@@ -2559,9 +2557,8 @@ restart_loop:
 		wbc->nr_to_write = to_write;
 	}
 
-	if (wbc->range_cont && (pages_skipped != wbc->pages_skipped)) {
+	if (!wbc->range_cyclic && (pages_skipped != wbc->pages_skipped)) {
 		/* We skipped pages in this loop */
-		wbc->range_start = range_start;
 		wbc->nr_to_write = to_write +
 				wbc->pages_skipped - pages_skipped;
 		wbc->pages_skipped = pages_skipped;
@@ -2570,7 +2567,6 @@ restart_loop:
 
 out_writepages:
 	wbc->nr_to_write = to_write - nr_to_writebump;
-	wbc->range_start = range_start;
 	return ret;
 }
 


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch percpu-counter-clean-up-percpu_counter_sum_and_set.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: percpu counter: clean up percpu_counter_sum_and_set()

to the 2.6.27-stable tree.  Its filename is

    percpu-counter-clean-up-percpu_counter_sum_and_set.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:20:04 2010
From: Mingming Cao <cmm@us.ibm.com>
Date: Mon, 15 Mar 2010 20:25:56 -0400
Subject: percpu counter: clean up percpu_counter_sum_and_set()
To: stable@kernel.org
Cc: "Theodore Ts'o" <tytso@mit.edu>, Andrew Morton <akpm@linux-foundation.org>, Ext4 Developers List <linux-ext4@vger.kernel.org>, Mingming Cao <cmm@us.ibm.com>, "Jayson R. King" <dev@jaysonking.com>
Message-ID: <1268699165-17461-3-git-send-email-tytso@mit.edu>


From: Mingming Cao <cmm@us.ibm.com>

commit 1f7c14c62ce63805f9574664a6c6de3633d4a354 upstream.

percpu_counter_sum_and_set() and percpu_counter_sum() is the same except
the former updates the global counter after accounting.  Since we are
taking the fbc->lock to calculate the precise value of the counter in
percpu_counter_sum() anyway, it should simply set fbc->count too, as the
percpu_counter_sum_and_set() does.

This patch merges these two interfaces into one.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

---
 fs/ext4/balloc.c               |    2 +-
 include/linux/percpu_counter.h |   12 +++---------
 lib/percpu_counter.c           |    8 +++-----
 3 files changed, 7 insertions(+), 15 deletions(-)

--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -1778,7 +1778,7 @@ ext4_fsblk_t ext4_has_free_blocks(struct
 #ifdef CONFIG_SMP
 	if (free_blocks - root_blocks < FBC_BATCH)
 		free_blocks =
-			percpu_counter_sum_and_set(&sbi->s_freeblocks_counter);
+			percpu_counter_sum(&sbi->s_freeblocks_counter);
 #endif
 	if (free_blocks <= root_blocks)
 		/* we don't have free space */
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -35,7 +35,7 @@ int percpu_counter_init_irq(struct percp
 void percpu_counter_destroy(struct percpu_counter *fbc);
 void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
-s64 __percpu_counter_sum(struct percpu_counter *fbc, int set);
+s64 __percpu_counter_sum(struct percpu_counter *fbc);
 
 static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 {
@@ -44,19 +44,13 @@ static inline void percpu_counter_add(st
 
 static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
 {
-	s64 ret = __percpu_counter_sum(fbc, 0);
+	s64 ret = __percpu_counter_sum(fbc);
 	return ret < 0 ? 0 : ret;
 }
 
-static inline s64 percpu_counter_sum_and_set(struct percpu_counter *fbc)
-{
-	return __percpu_counter_sum(fbc, 1);
-}
-
-
 static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
 {
-	return __percpu_counter_sum(fbc, 0);
+	return __percpu_counter_sum(fbc);
 }
 
 static inline s64 percpu_counter_read(struct percpu_counter *fbc)
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -52,7 +52,7 @@ EXPORT_SYMBOL(__percpu_counter_add);
  * Add up all the per-cpu counts, return the result.  This is a more accurate
  * but much slower version of percpu_counter_read_positive()
  */
-s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
+s64 __percpu_counter_sum(struct percpu_counter *fbc)
 {
 	s64 ret;
 	int cpu;
@@ -62,11 +62,9 @@ s64 __percpu_counter_sum(struct percpu_c
 	for_each_online_cpu(cpu) {
 		s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
 		ret += *pcount;
-		if (set)
-			*pcount = 0;
+		*pcount = 0;
 	}
-	if (set)
-		fbc->count = ret;
+	fbc->count = ret;
 
 	spin_unlock(&fbc->lock);
 	return ret;


Patches currently in stable-queue which might be from cmm@us.ibm.com are

queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/percpu-counter-clean-up-percpu_counter_sum_and_set.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch vfs-add-no_nrwrite_index_update-writeback-control-flag.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: vfs: Add no_nrwrite_index_update writeback control flag

to the 2.6.27-stable tree.  Its filename is

    vfs-add-no_nrwrite_index_update-writeback-control-flag.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:23:14 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:26:03 -0400
Subject: vfs: Add no_nrwrite_index_update writeback control flag
To: stable@kernel.org
Cc: linux-fsdevel@vger.kernel.org, Ext4 Developers List <linux-ext4@vger.kernel.org>, "Theodore Ts'o" <tytso@mit.edu>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-10-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 17bc6c30cf6bfffd816bdc53682dd46fc34a2cf4 upstream.

If no_nrwrite_index_update is set we don't update nr_to_write and
address space writeback_index in write_cache_pages.  This change
enables a file system to skip these updates in write_cache_pages and do
them in the writepages() callback.  This patch will be followed by an
ext4 patch that make use of these new flags.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
CC: linux-fsdevel@vger.kernel.org
[dev@jaysonking.com: Modified the patch to account for subsequent changes in mainline being cherry-picked earlier for 2.6.27.y.]
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 include/linux/writeback.h |    9 +++++++++
 mm/page-writeback.c       |   14 +++++++++-----
 2 files changed, 18 insertions(+), 5 deletions(-)

--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -62,6 +62,15 @@ struct writeback_control {
 	unsigned for_writepages:1;	/* This is a writepages() call */
 	unsigned range_cyclic:1;	/* range_start is cyclic */
 	unsigned more_io:1;		/* more io to be dispatched */
+	/*
+	 * write_cache_pages() won't update wbc->nr_to_write and
+	 * mapping->writeback_index if no_nrwrite_index_update
+	 * is set.  write_cache_pages() may write more than we
+	 * requested and we want to make sure nr_to_write and
+	 * writeback_index are updated in a consistent manner
+	 * so we use a single control to update them
+	 */
+	unsigned no_nrwrite_index_update:1;
 };
 
 /*
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -878,6 +878,7 @@ int write_cache_pages(struct address_spa
 	pgoff_t done_index;
 	int cycled;
 	int range_whole = 0;
+	long nr_to_write = wbc->nr_to_write;
 
 	if (wbc->nonblocking && bdi_write_congested(bdi)) {
 		wbc->encountered_congestion = 1;
@@ -985,9 +986,9 @@ continue_unlock:
 				}
  			}
 
-			if (wbc->nr_to_write > 0) {
-				wbc->nr_to_write--;
-				if (wbc->nr_to_write == 0 &&
+			if (nr_to_write > 0) {
+				nr_to_write--;
+				if (nr_to_write == 0 &&
 				    wbc->sync_mode == WB_SYNC_NONE) {
 					/*
 					 * We stop writing back only if we are
@@ -1024,8 +1025,11 @@ continue_unlock:
 		end = writeback_index - 1;
 		goto retry;
 	}
-	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
-		mapping->writeback_index = done_index;
+	if (!wbc->no_nrwrite_index_update) {
+		if (wbc->range_cyclic || (range_whole && nr_to_write > 0))
+			mapping->writeback_index = done_index;
+		wbc->nr_to_write = nr_to_write;
+	}
 
 	return ret;
 }


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch

patch vfs-remove-the-range_cont-writeback-mode.patch added to 2.6.27-stable tree

[gregkh]

This is a note to let you know that we have just queued up the patch titled

    Subject: vfs: Remove the range_cont writeback mode.

to the 2.6.27-stable tree.  Its filename is

    vfs-remove-the-range_cont-writeback-mode.patch

A git repo of this tree can be found at 
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary


>From tytso@mit.edu  Mon Apr 19 10:22:47 2010
From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Mon, 15 Mar 2010 20:26:02 -0400
Subject: vfs: Remove the range_cont writeback mode.
To: stable@kernel.org
Cc: linux-fsdevel@vger.kernel.org, Ext4 Developers List <linux-ext4@vger.kernel.org>, "Theodore Ts'o" <tytso@mit.edu>, "Jayson R. King" <dev@jaysonking.com>, "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Message-ID: <1268699165-17461-9-git-send-email-tytso@mit.edu>


From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

commit 74baaaaec8b4f22e1ae279f5ecca4ff705b28912 upstream.

Ext4 was the only user of range_cont writeback mode and ext4 switched
to a different method. So remove the range_cont mode which is not used
in the kernel.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: Jayson R. King <dev@jaysonking.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 include/linux/writeback.h |    1 -
 mm/page-writeback.c       |    2 --
 2 files changed, 3 deletions(-)

--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -62,7 +62,6 @@ struct writeback_control {
 	unsigned for_writepages:1;	/* This is a writepages() call */
 	unsigned range_cyclic:1;	/* range_start is cyclic */
 	unsigned more_io:1;		/* more io to be dispatched */
-	unsigned range_cont:1;
 };
 
 /*
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1027,8 +1027,6 @@ continue_unlock:
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		mapping->writeback_index = done_index;
 
-	if (wbc->range_cont)
-		wbc->range_start = index << PAGE_CACHE_SHIFT;
 	return ret;
 }
 EXPORT_SYMBOL(write_cache_pages);


Patches currently in stable-queue which might be from aneesh.kumar@linux.vnet.ibm.com are

queue-2.6.27/ext4-fix-file-fragmentation-during-large-file-write.patch
queue-2.6.27/ext4-retry-block-allocation-if-we-have-free-blocks-left.patch
queue-2.6.27/vfs-add-no_nrwrite_index_update-writeback-control-flag.patch
queue-2.6.27/ext4-retry-block-reservation.patch
queue-2.6.27/ext4-invalidate-pages-if-delalloc-block-allocation-fails.patch
queue-2.6.27/ext4-use-tag-dirty-lookup-during-mpage_da_submit_io.patch
queue-2.6.27/vfs-remove-the-range_cont-writeback-mode.patch
queue-2.6.27/ext4-make-sure-all-the-block-allocation-paths-reserve-blocks.patch
queue-2.6.27/ext4-implement-range_cyclic-in-ext4_da_writepages-instead-of-write_cache_pages.patch
queue-2.6.27/ext4-add-percpu-dirty-block-accounting.patch