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From: Eric Biggers <ebiggers@kernel.org>
To: linux-fsdevel@vger.kernel.org
Cc: linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	Theodore Ts'o <tytso@mit.edu>, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v2 07/12] fs: clean up __mark_inode_dirty() a bit
Date: Fri,  8 Jan 2021 23:58:58 -0800	[thread overview]
Message-ID: <20210109075903.208222-8-ebiggers@kernel.org> (raw)
In-Reply-To: <20210109075903.208222-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

Improve some comments, and don't bother checking for the I_DIRTY_TIME
flag in the case where we just cleared it.

Also, warn if I_DIRTY_TIME and I_DIRTY_PAGES are passed to
__mark_inode_dirty() at the same time, as this case isn't handled.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/fs-writeback.c | 49 +++++++++++++++++++++++++++++------------------
 1 file changed, 30 insertions(+), 19 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 2e6064012f7d3..80ee9816d9df5 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -2219,23 +2219,24 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode)
 }
 
 /**
- * __mark_inode_dirty -	internal function
+ * __mark_inode_dirty -	internal function to mark an inode dirty
  *
  * @inode: inode to mark
- * @flags: what kind of dirty (i.e. I_DIRTY_SYNC)
+ * @flags: what kind of dirty, e.g. I_DIRTY_SYNC.  This can be a combination of
+ *	   multiple I_DIRTY_* flags, except that I_DIRTY_TIME can't be combined
+ *	   with I_DIRTY_PAGES.
  *
- * Mark an inode as dirty. Callers should use mark_inode_dirty or
- * mark_inode_dirty_sync.
+ * Mark an inode as dirty.  We notify the filesystem, then update the inode's
+ * dirty flags.  Then, if needed we add the inode to the appropriate dirty list.
  *
- * Put the inode on the super block's dirty list.
+ * Most callers should use mark_inode_dirty() or mark_inode_dirty_sync()
+ * instead of calling this directly.
  *
- * CAREFUL! We mark it dirty unconditionally, but move it onto the
- * dirty list only if it is hashed or if it refers to a blockdev.
- * If it was not hashed, it will never be added to the dirty list
- * even if it is later hashed, as it will have been marked dirty already.
+ * CAREFUL!  We only add the inode to the dirty list if it is hashed or if it
+ * refers to a blockdev.  Unhashed inodes will never be added to the dirty list
+ * even if they are later hashed, as they will have been marked dirty already.
  *
- * In short, make sure you hash any inodes _before_ you start marking
- * them dirty.
+ * In short, ensure you hash any inodes _before_ you start marking them dirty.
  *
  * Note that for blockdevs, inode->dirtied_when represents the dirtying time of
  * the block-special inode (/dev/hda1) itself.  And the ->dirtied_when field of
@@ -2247,25 +2248,34 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode)
 void __mark_inode_dirty(struct inode *inode, int flags)
 {
 	struct super_block *sb = inode->i_sb;
-	int dirtytime;
+	int dirtytime = 0;
 
 	trace_writeback_mark_inode_dirty(inode, flags);
 
-	/*
-	 * Don't do this for I_DIRTY_PAGES - that doesn't actually
-	 * dirty the inode itself
-	 */
 	if (flags & I_DIRTY_INODE) {
+		/*
+		 * Notify the filesystem about the inode being dirtied, so that
+		 * (if needed) it can update on-disk fields and journal the
+		 * inode.  This is only needed when the inode itself is being
+		 * dirtied now.  I.e. it's only needed for I_DIRTY_INODE, not
+		 * for just I_DIRTY_PAGES or I_DIRTY_TIME.
+		 */
 		trace_writeback_dirty_inode_start(inode, flags);
-
 		if (sb->s_op->dirty_inode)
 			sb->s_op->dirty_inode(inode, flags & I_DIRTY_INODE);
-
 		trace_writeback_dirty_inode(inode, flags);
 
+		/* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
 		flags &= ~I_DIRTY_TIME;
+	} else {
+		/*
+		 * Else it's either I_DIRTY_PAGES, I_DIRTY_TIME, or nothing.
+		 * (We don't support setting both I_DIRTY_PAGES and I_DIRTY_TIME
+		 * in one call to __mark_inode_dirty().)
+		 */
+		dirtytime = flags & I_DIRTY_TIME;
+		WARN_ON_ONCE(dirtytime && flags != I_DIRTY_TIME);
 	}
-	dirtytime = flags & I_DIRTY_TIME;
 
 	/*
 	 * Paired with smp_mb() in __writeback_single_inode() for the
@@ -2288,6 +2298,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
 
 		inode_attach_wb(inode, NULL);
 
+		/* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
 		if (flags & I_DIRTY_INODE)
 			inode->i_state &= ~I_DIRTY_TIME;
 		inode->i_state |= flags;
-- 
2.30.0


WARNING: multiple messages have this Message-ID
From: Eric Biggers <ebiggers@kernel.org>
To: linux-fsdevel@vger.kernel.org
Cc: linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
	Theodore Ts'o <tytso@mit.edu>, Christoph Hellwig <hch@lst.de>,
	linux-f2fs-devel@lists.sourceforge.net
Subject: [f2fs-dev] [PATCH v2 07/12] fs: clean up __mark_inode_dirty() a bit
Date: Fri,  8 Jan 2021 23:58:58 -0800	[thread overview]
Message-ID: <20210109075903.208222-8-ebiggers@kernel.org> (raw)
In-Reply-To: <20210109075903.208222-1-ebiggers@kernel.org>

From: Eric Biggers <ebiggers@google.com>

Improve some comments, and don't bother checking for the I_DIRTY_TIME
flag in the case where we just cleared it.

Also, warn if I_DIRTY_TIME and I_DIRTY_PAGES are passed to
__mark_inode_dirty() at the same time, as this case isn't handled.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/fs-writeback.c | 49 +++++++++++++++++++++++++++++------------------
 1 file changed, 30 insertions(+), 19 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 2e6064012f7d3..80ee9816d9df5 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -2219,23 +2219,24 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode)
 }
 
 /**
- * __mark_inode_dirty -	internal function
+ * __mark_inode_dirty -	internal function to mark an inode dirty
  *
  * @inode: inode to mark
- * @flags: what kind of dirty (i.e. I_DIRTY_SYNC)
+ * @flags: what kind of dirty, e.g. I_DIRTY_SYNC.  This can be a combination of
+ *	   multiple I_DIRTY_* flags, except that I_DIRTY_TIME can't be combined
+ *	   with I_DIRTY_PAGES.
  *
- * Mark an inode as dirty. Callers should use mark_inode_dirty or
- * mark_inode_dirty_sync.
+ * Mark an inode as dirty.  We notify the filesystem, then update the inode's
+ * dirty flags.  Then, if needed we add the inode to the appropriate dirty list.
  *
- * Put the inode on the super block's dirty list.
+ * Most callers should use mark_inode_dirty() or mark_inode_dirty_sync()
+ * instead of calling this directly.
  *
- * CAREFUL! We mark it dirty unconditionally, but move it onto the
- * dirty list only if it is hashed or if it refers to a blockdev.
- * If it was not hashed, it will never be added to the dirty list
- * even if it is later hashed, as it will have been marked dirty already.
+ * CAREFUL!  We only add the inode to the dirty list if it is hashed or if it
+ * refers to a blockdev.  Unhashed inodes will never be added to the dirty list
+ * even if they are later hashed, as they will have been marked dirty already.
  *
- * In short, make sure you hash any inodes _before_ you start marking
- * them dirty.
+ * In short, ensure you hash any inodes _before_ you start marking them dirty.
  *
  * Note that for blockdevs, inode->dirtied_when represents the dirtying time of
  * the block-special inode (/dev/hda1) itself.  And the ->dirtied_when field of
@@ -2247,25 +2248,34 @@ static noinline void block_dump___mark_inode_dirty(struct inode *inode)
 void __mark_inode_dirty(struct inode *inode, int flags)
 {
 	struct super_block *sb = inode->i_sb;
-	int dirtytime;
+	int dirtytime = 0;
 
 	trace_writeback_mark_inode_dirty(inode, flags);
 
-	/*
-	 * Don't do this for I_DIRTY_PAGES - that doesn't actually
-	 * dirty the inode itself
-	 */
 	if (flags & I_DIRTY_INODE) {
+		/*
+		 * Notify the filesystem about the inode being dirtied, so that
+		 * (if needed) it can update on-disk fields and journal the
+		 * inode.  This is only needed when the inode itself is being
+		 * dirtied now.  I.e. it's only needed for I_DIRTY_INODE, not
+		 * for just I_DIRTY_PAGES or I_DIRTY_TIME.
+		 */
 		trace_writeback_dirty_inode_start(inode, flags);
-
 		if (sb->s_op->dirty_inode)
 			sb->s_op->dirty_inode(inode, flags & I_DIRTY_INODE);
-
 		trace_writeback_dirty_inode(inode, flags);
 
+		/* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
 		flags &= ~I_DIRTY_TIME;
+	} else {
+		/*
+		 * Else it's either I_DIRTY_PAGES, I_DIRTY_TIME, or nothing.
+		 * (We don't support setting both I_DIRTY_PAGES and I_DIRTY_TIME
+		 * in one call to __mark_inode_dirty().)
+		 */
+		dirtytime = flags & I_DIRTY_TIME;
+		WARN_ON_ONCE(dirtytime && flags != I_DIRTY_TIME);
 	}
-	dirtytime = flags & I_DIRTY_TIME;
 
 	/*
 	 * Paired with smp_mb() in __writeback_single_inode() for the
@@ -2288,6 +2298,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
 
 		inode_attach_wb(inode, NULL);
 
+		/* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
 		if (flags & I_DIRTY_INODE)
 			inode->i_state &= ~I_DIRTY_TIME;
 		inode->i_state |= flags;
-- 
2.30.0



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  parent reply	other threads:[~2021-01-09  8:01 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-09  7:58 [PATCH v2 00/12] lazytime fix and cleanups Eric Biggers
2021-01-09  7:58 ` [f2fs-dev] " Eric Biggers
2021-01-09  7:58 ` [PATCH v2 01/12] fs: fix lazytime expiration handling in __writeback_single_inode() Eric Biggers
2021-01-09  7:58   ` [f2fs-dev] " Eric Biggers
2021-01-11 10:48   ` Christoph Hellwig
2021-01-11 10:48     ` [f2fs-dev] " Christoph Hellwig
2021-01-11 14:46   ` Jan Kara
2021-01-11 14:46     ` [f2fs-dev] " Jan Kara
2021-01-09  7:58 ` [PATCH v2 02/12] fs: correctly document the inode dirty flags Eric Biggers
2021-01-09  7:58   ` [f2fs-dev] " Eric Biggers
2021-01-11 14:48   ` Jan Kara
2021-01-11 14:48     ` [f2fs-dev] " Jan Kara
2021-01-09  7:58 ` [PATCH v2 03/12] fs: only specify I_DIRTY_TIME when needed in generic_update_time() Eric Biggers
2021-01-09  7:58   ` [f2fs-dev] " Eric Biggers
2021-01-11 14:50   ` Jan Kara
2021-01-11 14:50     ` [f2fs-dev] " Jan Kara
2021-01-09  7:58 ` [PATCH v2 04/12] fat: only specify I_DIRTY_TIME when needed in fat_update_time() Eric Biggers
2021-01-09  7:58   ` [f2fs-dev] " Eric Biggers
2021-01-11 10:52   ` Christoph Hellwig
2021-01-11 10:52     ` [f2fs-dev] " Christoph Hellwig
2021-01-11 19:50     ` Eric Biggers
2021-01-11 19:50       ` [f2fs-dev] " Eric Biggers
2021-01-12  5:21       ` Dave Chinner
2021-01-12  5:21         ` [f2fs-dev] " Dave Chinner
2021-01-12 13:23       ` Christoph Hellwig
2021-01-12 13:23         ` [f2fs-dev] " Christoph Hellwig
2021-01-11 14:52   ` Jan Kara
2021-01-11 14:52     ` [f2fs-dev] " Jan Kara
2021-01-09  7:58 ` [PATCH v2 05/12] fs: don't call ->dirty_inode for lazytime timestamp updates Eric Biggers
2021-01-09  7:58   ` [f2fs-dev] " Eric Biggers
2021-01-11 14:54   ` Jan Kara
2021-01-11 14:54     ` [f2fs-dev] " Jan Kara
2021-01-09  7:58 ` [PATCH v2 06/12] fs: pass only I_DIRTY_INODE flags to ->dirty_inode Eric Biggers
2021-01-09  7:58   ` [f2fs-dev] " Eric Biggers
2021-01-11 14:56   ` Jan Kara
2021-01-11 14:56     ` [f2fs-dev] " Jan Kara
2021-01-09  7:58 ` Eric Biggers [this message]
2021-01-09  7:58   ` [f2fs-dev] [PATCH v2 07/12] fs: clean up __mark_inode_dirty() a bit Eric Biggers
2021-01-11 14:59   ` Jan Kara
2021-01-11 14:59     ` [f2fs-dev] " Jan Kara
2021-01-09  7:58 ` [PATCH v2 08/12] fs: drop redundant check from __writeback_single_inode() Eric Biggers
2021-01-09  7:58   ` [f2fs-dev] " Eric Biggers
2021-01-11 10:52   ` Christoph Hellwig
2021-01-11 10:52     ` [f2fs-dev] " Christoph Hellwig
2021-01-11 15:00   ` Jan Kara
2021-01-11 15:00     ` [f2fs-dev] " Jan Kara
2021-01-09  7:59 ` [PATCH v2 09/12] fs: improve comments for writeback_single_inode() Eric Biggers
2021-01-09  7:59   ` [f2fs-dev] " Eric Biggers
2021-01-11 10:53   ` Christoph Hellwig
2021-01-11 10:53     ` [f2fs-dev] " Christoph Hellwig
2021-01-11 15:05   ` Jan Kara
2021-01-11 15:05     ` [f2fs-dev] " Jan Kara
2021-01-09  7:59 ` [PATCH v2 10/12] gfs2: don't worry about I_DIRTY_TIME in gfs2_fsync() Eric Biggers
2021-01-09  7:59   ` [f2fs-dev] " Eric Biggers
2021-01-11 15:06   ` Jan Kara
2021-01-11 15:06     ` [f2fs-dev] " Jan Kara
2021-01-09  7:59 ` [PATCH v2 11/12] ext4: simplify i_state checks in __ext4_update_other_inode_time() Eric Biggers
2021-01-09  7:59   ` [f2fs-dev] " Eric Biggers
2021-01-11 10:53   ` Christoph Hellwig
2021-01-11 10:53     ` [f2fs-dev] " Christoph Hellwig
2021-01-11 20:23     ` Eric Biggers
2021-01-11 20:23       ` [f2fs-dev] " Eric Biggers
2021-01-12 13:25       ` Christoph Hellwig
2021-01-12 13:25         ` [f2fs-dev] " Christoph Hellwig
2021-02-03  5:16         ` Theodore Ts'o
2021-02-03  5:16           ` [f2fs-dev] " Theodore Ts'o
2021-01-11 15:11   ` Jan Kara
2021-01-11 15:11     ` [f2fs-dev] " Jan Kara
2021-01-09  7:59 ` [PATCH v2 12/12] xfs: remove a stale comment from xfs_file_aio_write_checks() Eric Biggers
2021-01-09  7:59   ` [f2fs-dev] " Eric Biggers
2021-01-12 17:31   ` Darrick J. Wong
2021-01-12 17:31     ` [f2fs-dev] " Darrick J. Wong
2021-01-11 15:15 ` [PATCH v2 00/12] lazytime fix and cleanups Jan Kara
2021-01-11 15:15   ` [f2fs-dev] " Jan Kara
2021-01-11 20:44   ` Eric Biggers
2021-01-11 20:44     ` [f2fs-dev] " Eric Biggers
2021-02-03  5:11     ` Theodore Ts'o
2021-02-03  5:11       ` [f2fs-dev] " Theodore Ts'o
2021-02-03  5:22       ` Eric Biggers
2021-02-03  5:22         ` [f2fs-dev] " Eric Biggers
2021-02-03 15:49         ` Theodore Ts'o
2021-02-03 15:49           ` [f2fs-dev] " Theodore Ts'o

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