From: Mark Fasheh <mfasheh@suse.de>
To: Jan Schmidt <list.btrfs@jan-o-sch.net>
Cc: linux-btrfs@vger.kernel.org, Chris Mason <chris.mason@fusionio.com>
Subject: Re: [PATCH 2/3] btrfs: extended inode refs
Date: Wed, 15 Aug 2012 10:59:35 -0700 [thread overview]
Message-ID: <20120815175933.GE15159@wotan.suse.de> (raw)
In-Reply-To: <502BBA90.90403@jan-o-sch.net>
On Wed, Aug 15, 2012 at 05:04:48PM +0200, Jan Schmidt wrote:
> When applying this patch I get:
>
> warning: 2 lines add whitespace errors.
>
Oop, I'll fix that up.
> More comments inline.
>
> On Wed, August 08, 2012 at 20:55 (+0200), Mark Fasheh wrote:
> > Teach tree-log.c about extended inode refs. In particular, we have to adjust
> > the behavior of inode ref replay as well as log tree recovery to account for
> > the existence of extended refs.
> >
> > Signed-off-by: Mark Fasheh <mfasheh@suse.de>
> > ---
> > fs/btrfs/backref.c | 68 ++++++++++++
> > fs/btrfs/backref.h | 5 +
> > fs/btrfs/tree-log.c | 297 ++++++++++++++++++++++++++++++++++++++++++---------
> > 3 files changed, 319 insertions(+), 51 deletions(-)
> >
> > diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> > index a383c18..658e09c 100644
> > --- a/fs/btrfs/backref.c
> > +++ b/fs/btrfs/backref.c
> > @@ -1111,6 +1111,74 @@ static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
> > found_key);
> > }
> >
> > +int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
> > + u64 start_off, struct btrfs_path *path,
> > + struct btrfs_inode_extref **ret_extref,
> > + u64 *found_off)
> > +{
> > + int ret, slot;
> > + struct btrfs_key key;
> > + struct btrfs_key found_key;
> > + struct btrfs_inode_extref *extref;
> > + struct extent_buffer *leaf;
> > + unsigned long ptr;
> > +
> > + key.objectid = inode_objectid;
> > + btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
> > + key.offset = start_off;
> > +
> > + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
> > + if (ret < 0)
> > + return ret;
> > +
> > + while (1) {
> > + leaf = path->nodes[0];
> > + slot = path->slots[0];
> > + if (slot >= btrfs_header_nritems(leaf)) {
> > + /*
> > + * If the item at offset is not found,
> > + * btrfs_search_slot will point us to the slot
> > + * where it should be inserted. In our case
> > + * that will be the slot directly before the
> > + * next INODE_REF_KEY_V2 item. In the case
> > + * that we're pointing to the last slot in a
> > + * leaf, we must move one leaf over.
> > + */
> > + ret = btrfs_next_leaf(root, path);
> > + if (ret) {
> > + if (ret >= 1)
> > + ret = -ENOENT;
> > + break;
> > + }
>
> We can finally replace this with btrfs_search_slot_for_read, according to my
> first suggestion. It's merged now. Saves that long comment and the whole
> while-1-continue construct, which is quite cumbersome to read.
Alright, I'll take a look at this. I need to read
btrfs_search_slot_for_read() first to make sure it all fits correctly.
> > + continue;
> > + }
> > +
> > + btrfs_item_key_to_cpu(leaf, &found_key, slot);
> > +
> > + /*
> > + * Check that we're still looking at an extended ref key for
> > + * this particular objectid. If we have different
> > + * objectid or type then there are no more to be found
> > + * in the tree and we can exit.
> > + */
> > + ret = -ENOENT;
> > + if (found_key.objectid != inode_objectid)
> > + break;
> > + if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY)
> > + break;
> > +
> > + ret = 0;
> > + ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
> > + extref = (struct btrfs_inode_extref *)ptr;
> > + *ret_extref = extref;
> > + if (found_off)
> > + *found_off = found_key.offset;
> > + break;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > /*
> > * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
> > * of the path are separated by '/' and the path is guaranteed to be
> > diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
> > index c18d8ac..9f3e251 100644
> > --- a/fs/btrfs/backref.h
> > +++ b/fs/btrfs/backref.h
> > @@ -66,4 +66,9 @@ struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
> > struct btrfs_path *path);
> > void free_ipath(struct inode_fs_paths *ipath);
> >
> > +int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
> > + u64 start_off, struct btrfs_path *path,
> > + struct btrfs_inode_extref **ret_extref,
> > + u64 *found_off);
> > +
> > #endif
> > diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> > index 8abeae4..e5ba0a4 100644
> > --- a/fs/btrfs/tree-log.c
> > +++ b/fs/btrfs/tree-log.c
> > @@ -23,8 +23,10 @@
> > #include "disk-io.h"
> > #include "locking.h"
> > #include "print-tree.h"
> > +#include "backref.h"
> > #include "compat.h"
> > #include "tree-log.h"
> > +#include "hash.h"
> >
> > /* magic values for the inode_only field in btrfs_log_inode:
> > *
> > @@ -764,8 +766,16 @@ static noinline int backref_in_log(struct btrfs_root *log,
> > if (ret != 0)
> > goto out;
> >
> > - item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
> > ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
> > +
> > + if (key->type == BTRFS_INODE_EXTREF_KEY) {
> > + if (btrfs_find_name_in_ext_backref(path, name, namelen, NULL))
> > + match = 1;
> > +
> > + goto out;
> > + }
> > +
> > + item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
> > ptr_end = ptr + item_size;
> > while (ptr < ptr_end) {
> > ref = (struct btrfs_inode_ref *)ptr;
> > @@ -786,6 +796,47 @@ out:
> > return match;
> > }
> >
> > +static int extref_get_fields(struct extent_buffer *eb, int slot,
> > + u32 *namelen, char **name, u64 *index,
> > + u64 *parent_objectid)
> > +{
> > + struct btrfs_inode_extref *extref;
> > +
> > + extref = (struct btrfs_inode_extref *)btrfs_item_ptr_offset(eb, slot);
> > +
> > + *namelen = btrfs_inode_extref_name_len(eb, extref);
> > + *name = kmalloc(*namelen, GFP_NOFS);
> > + if (*name == NULL)
> > + return -ENOMEM;
> > +
> > + read_extent_buffer(eb, *name, (unsigned long)&extref->name,
> > + *namelen);
> > +
> > + *index = btrfs_inode_extref_index(eb, extref);
> > + if (parent_objectid)
> > + *parent_objectid = btrfs_inode_extref_parent(eb, extref);
> > +
> > + return 0;
> > +}
> > +
> > +static int ref_get_fields(struct extent_buffer *eb, int slot, u32 *namelen,
> > + char **name, u64 *index)
> > +{
> > + struct btrfs_inode_ref *ref;
> > +
> > + ref = (struct btrfs_inode_ref *)btrfs_item_ptr_offset(eb, slot);
> > +
> > + *namelen = btrfs_inode_ref_name_len(eb, ref);
> > + *name = kmalloc(*namelen, GFP_NOFS);
> > + if (*name == NULL)
> > + return -ENOMEM;
> > +
> > + read_extent_buffer(eb, *name, (unsigned long)(ref + 1), *namelen);
> > +
> > + *index = btrfs_inode_ref_index(eb, ref);
> > +
> > + return 0;
> > +}
> >
> > /*
> > * replay one inode back reference item found in the log tree.
> > @@ -801,15 +852,50 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
> > struct btrfs_key *key)
>
> Control flow in this function is horrible. I finally failed to understand it.
> That's why I made a patch that replaces most gotos by if blocks and uses a sub
> function (see the end of this email). I hope that it's getting easier to extend
> that patched version. Cannot comment on changes to code I don't understand, sorry.
I *think* I understand most of it, after much much reading and re-reading. I
really am not confident enough though to say anything on the matter until
Chris weighs in.
> If you find my patch helps understanding that function and makes patching
> easier, you can include that patch in your patch set as patch 2/4 and then do
> your extension afterwards.
Thanks, I'll take a look at your patch. I think any attempt to clean it up
will be nicely recieved.
> > {
> > struct btrfs_inode_ref *ref;
> > + struct btrfs_inode_extref *extref;
> > struct btrfs_dir_item *di;
> > + struct btrfs_key search_key;
> > struct inode *dir;
> > struct inode *inode;
> > unsigned long ref_ptr;
> > unsigned long ref_end;
> > char *name;
> > + char *victim_name;
> > int namelen;
> > + int victim_name_len;
> > int ret;
> > int search_done = 0;
> > + int log_ref_ver = 0;
> > + u64 parent_objectid;
> > + u64 inode_objectid;
> > + u64 ref_index;
> > + struct extent_buffer *leaf;
> > + int ref_struct_size;
> > +
> > +
> > + ref_ptr = btrfs_item_ptr_offset(eb, slot);
> > + ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
> > +
> > + if (key->type == BTRFS_INODE_EXTREF_KEY) {
> > + ref_struct_size = sizeof(*extref);
> > + log_ref_ver = 1;
> > +
> > + ret = extref_get_fields(eb, slot, &namelen, &name, &ref_index,
> > + &parent_objectid);
> > + if (ret)
> > + return ret;
> > + } else {
> > + ref_struct_size = sizeof(*ref);
> > +
> > + ret = ref_get_fields(eb, slot, &namelen, &name, &ref_index);
> > + if (ret)
> > + return ret;
> > +
> > +
> > + parent_objectid = key->offset;
> > + }
> > +
> > + inode_objectid = key->objectid;
> >
> > /*
> > * it is possible that we didn't log all the parent directories
> > @@ -817,32 +903,20 @@ static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
> > * copy the back ref in. The link count fixup code will take
> > * care of the rest
> > */
> > - dir = read_one_inode(root, key->offset);
> > + dir = read_one_inode(root, parent_objectid);
> > if (!dir)
> > return -ENOENT;
> >
> > - inode = read_one_inode(root, key->objectid);
> > + inode = read_one_inode(root, inode_objectid);
> > if (!inode) {
> > iput(dir);
> > return -EIO;
> > }
> >
> > - ref_ptr = btrfs_item_ptr_offset(eb, slot);
> > - ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
> > -
> > again:
> > - ref = (struct btrfs_inode_ref *)ref_ptr;
> > -
> > - namelen = btrfs_inode_ref_name_len(eb, ref);
> > - name = kmalloc(namelen, GFP_NOFS);
> > - BUG_ON(!name);
> > -
> > - read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
> > -
> > /* if we already have a perfect match, we're done */
> > if (inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
> > - btrfs_inode_ref_index(eb, ref),
> > - name, namelen)) {
> > + ref_index, name, namelen)) {
> > goto out;
> > }
> >
> > @@ -857,19 +931,23 @@ again:
> > if (search_done)
> > goto insert;
> >
> > - ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
> > + /* Search old style refs */
> > + search_key.objectid = inode_objectid;
> > + search_key.type = BTRFS_INODE_REF_KEY;
> > + search_key.offset = parent_objectid;
> > +
> > + ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
> > if (ret == 0) {
> > - char *victim_name;
> > - int victim_name_len;
> > struct btrfs_inode_ref *victim_ref;
> > unsigned long ptr;
> > unsigned long ptr_end;
> > - struct extent_buffer *leaf = path->nodes[0];
> > +
> > + leaf = path->nodes[0];
> >
> > /* are we trying to overwrite a back ref for the root directory
> > * if so, just jump out, we're done
> > */
> > - if (key->objectid == key->offset)
> > + if (search_key.objectid == search_key.offset)
> > goto out_nowrite;
> >
> > /* check all the names in this back reference to see
> > @@ -889,7 +967,7 @@ again:
> > (unsigned long)(victim_ref + 1),
> > victim_name_len);
> >
> > - if (!backref_in_log(log, key, victim_name,
> > + if (!backref_in_log(log, &search_key, victim_name,
> > victim_name_len)) {
> > btrfs_inc_nlink(inode);
> > btrfs_release_path(path);
> > @@ -903,19 +981,61 @@ again:
> > ptr = (unsigned long)(victim_ref + 1) + victim_name_len;
> > }
> > BUG_ON(ret);
> > -
> > /*
> > * NOTE: we have searched root tree and checked the
> > - * coresponding ref, it does not need to check again.
> > + * coresponding refs, it does not need to be checked again.
> > */
> > search_done = 1;
> > }
> > btrfs_release_path(path);
> >
> > + /* Same search but for extended refs */
> > + extref = btrfs_lookup_inode_extref(NULL, root, path, name, namelen,
> > + inode_objectid, parent_objectid, 0,
> > + 0);
> > + if (!IS_ERR_OR_NULL(extref)) {
>
> Okay, one obvious comment at least: You don't execute this block on
> IS_ERR(extref), but you don't act on that situation either. Is that on purpose?
This is just mirroring the broken (or maybe misunderstood?) error handling
that this function has (unfortunately, all over the place). Basically, we
ignore errors from the lookups for either ref type.
> > + u32 item_size;
> > + u32 cur_offset = 0;
> > + unsigned long base;
> > +
> > + leaf = path->nodes[0];
> > +
> > + item_size = btrfs_item_size_nr(leaf, path->slots[0]);
> > + base = btrfs_item_ptr_offset(leaf, path->slots[0]);
> > +
> > + while (cur_offset < item_size) {
> > + extref = (struct btrfs_inode_extref *)base + cur_offset;
> > +
> > + victim_name_len = btrfs_inode_extref_name_len(eb, extref);
> > + victim_name = kmalloc(namelen, GFP_NOFS);
> > + leaf = path->nodes[0];
> > + read_extent_buffer(eb, name, (unsigned long)&extref->name, namelen);
> > +
> > + search_key.objectid = inode_objectid;
> > + search_key.type = BTRFS_INODE_EXTREF_KEY;
> > + search_key.offset = btrfs_extref_hash(parent_objectid,
> > + name, namelen);
> > + if (!backref_in_log(log, &search_key, victim_name,
> > + victim_name_len)) {
> > + btrfs_inc_nlink(inode);
> > + btrfs_release_path(path);
> > +
> > + ret = btrfs_unlink_inode(trans, root, dir,
> > + inode, victim_name,
> > + victim_name_len);
> > + }
> > + kfree(victim_name);
> > + BUG_ON(ret);
> > +
> > + cur_offset += victim_name_len + sizeof(*extref);
> > + }
> > + search_done = 1;
> > + }
> > +
> > +
> > /* look for a conflicting sequence number */
> > di = btrfs_lookup_dir_index_item(trans, root, path, btrfs_ino(dir),
> > - btrfs_inode_ref_index(eb, ref),
> > - name, namelen, 0);
> > + ref_index, name, namelen, 0);
> > if (di && !IS_ERR(di)) {
> > ret = drop_one_dir_item(trans, root, path, dir, di);
> > BUG_ON(ret);
> > @@ -933,17 +1053,25 @@ again:
> >
> > insert:
> > /* insert our name */
> > - ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,
> > - btrfs_inode_ref_index(eb, ref));
> > + ret = btrfs_add_link(trans, dir, inode, name, namelen, 0, ref_index);
> > BUG_ON(ret);
> >
> > btrfs_update_inode(trans, root, inode);
> >
> > out:
> > - ref_ptr = (unsigned long)(ref + 1) + namelen;
> > + ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + namelen;
> > kfree(name);
> > - if (ref_ptr < ref_end)
> > + if (ref_ptr < ref_end) {
> > + if (log_ref_ver) {
> > + ret = extref_get_fields(eb, slot, &namelen, &name,
> > + &ref_index, NULL);
> > + } else {
> > + ret = ref_get_fields(eb, slot, &namelen, &name,
> > + &ref_index);
> > + }
> > + BUG_ON(ret);
> > goto again;
> > + }
> >
> > /* finally write the back reference in the inode */
> > ret = overwrite_item(trans, root, path, eb, slot, key);
> > @@ -966,25 +1094,52 @@ static int insert_orphan_item(struct btrfs_trans_handle *trans,
> > return ret;
> > }
> >
> > +static int count_inode_extrefs(struct btrfs_root *root,
> > + struct inode *inode, struct btrfs_path *path)
> > +{
> > + int ret = 0;
> > + int name_len;
> > + unsigned int nlink = 0;
> > + u32 item_size;
> > + u32 cur_offset = 0;
> > + u64 inode_objectid = btrfs_ino(inode);
> > + u64 offset = 0;
> > + unsigned long ptr;
> > + struct btrfs_inode_extref *extref;
> > + struct extent_buffer *leaf;
> > +
> > + while (1) {
> > + ret = btrfs_find_one_extref(root, inode_objectid, offset, path,
> > + &extref, &offset);
> > + if (ret)
> > + break;
> >
> > -/*
> > - * There are a few corners where the link count of the file can't
> > - * be properly maintained during replay. So, instead of adding
> > - * lots of complexity to the log code, we just scan the backrefs
> > - * for any file that has been through replay.
> > - *
> > - * The scan will update the link count on the inode to reflect the
> > - * number of back refs found. If it goes down to zero, the iput
> > - * will free the inode.
> > - */
> > -static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
> > - struct btrfs_root *root,
> > - struct inode *inode)
> > + leaf = path->nodes[0];
> > + item_size = btrfs_item_size_nr(leaf, path->slots[0]);
> > + ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
> > +
> > + while (cur_offset < item_size) {
> > + extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
> > + name_len = btrfs_inode_extref_name_len(leaf, extref);
> > +
> > + nlink++;
> > +
> > + cur_offset += name_len + sizeof(*extref);
> > + }
> > +
> > + offset++;
> > + }
> > + btrfs_release_path(path);
> > +
> > + return (ret == 0) ? nlink : ret;
>
> You depend on btrfs_find_one_extref never returning >0 here. I'd make that ...
>
> if (ret < 0)
> return ret;
> return nlink;
>
> This ignores ret > 0 explicitly, which is in my opinion better than a spurious
> link count.
Sounds good.
> > +}
> > +
> > +static int count_inode_refs(struct btrfs_root *root,
> > + struct inode *inode, struct btrfs_path *path)
> > {
> > - struct btrfs_path *path;
> > int ret;
> > struct btrfs_key key;
> > - u64 nlink = 0;
> > + unsigned int nlink = 0;
> > unsigned long ptr;
> > unsigned long ptr_end;
> > int name_len;
> > @@ -994,10 +1149,6 @@ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
> > key.type = BTRFS_INODE_REF_KEY;
> > key.offset = (u64)-1;
> >
> > - path = btrfs_alloc_path();
> > - if (!path)
> > - return -ENOMEM;
> > -
> > while (1) {
> > ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
> > if (ret < 0)
> > @@ -1031,6 +1182,45 @@ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
> > btrfs_release_path(path);
> > }
> > btrfs_release_path(path);
> > +
> > + return nlink;
> > +}
> > +
> > +/*
> > + * There are a few corners where the link count of the file can't
> > + * be properly maintained during replay. So, instead of adding
> > + * lots of complexity to the log code, we just scan the backrefs
> > + * for any file that has been through replay.
> > + *
> > + * The scan will update the link count on the inode to reflect the
> > + * number of back refs found. If it goes down to zero, the iput
> > + * will free the inode.
> > + */
> > +static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
> > + struct btrfs_root *root,
> > + struct inode *inode)
> > +{
> > + struct btrfs_path *path;
> > + int ret;
> > + u64 nlink = 0;
> > + u64 ino = btrfs_ino(inode);
> > +
> > + path = btrfs_alloc_path();
> > + if (!path)
> > + return -ENOMEM;
> > +
> > + ret = count_inode_refs(root, inode, path);
> > + if (ret < 0)
> > + goto out;
> > +
> > + nlink = ret;
> > +
> > + ret = count_inode_extrefs(root, inode, path);
> > + if (ret < 0)
> > + goto out;
> > +
> > + nlink += ret;
> > +
> > if (nlink != inode->i_nlink) {
> > set_nlink(inode, nlink);
> > btrfs_update_inode(trans, root, inode);
> > @@ -1046,9 +1236,10 @@ static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
> > ret = insert_orphan_item(trans, root, ino);
> > BUG_ON(ret);
> > }
> > - btrfs_free_path(path);
> >
> > - return 0;
> > +out:
> > + btrfs_free_path(path);
> > + return ret;
> > }
> >
> > static noinline int fixup_inode_link_counts(struct btrfs_trans_handle *trans,
> > @@ -1695,6 +1886,10 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
> > ret = add_inode_ref(wc->trans, root, log, path,
> > eb, i, &key);
> > BUG_ON(ret && ret != -ENOENT);
> > + } else if (key.type == BTRFS_INODE_EXTREF_KEY) {
> > + ret = add_inode_ref(wc->trans, root, log, path,
> > + eb, i, &key);
> > + BUG_ON(ret && ret != -ENOENT);
> > } else if (key.type == BTRFS_EXTENT_DATA_KEY) {
> > ret = replay_one_extent(wc->trans, root, path,
> > eb, i, &key);
>
> That's it for this round, here comes the promised patch. Should apply with "git
> am --scissors".
Fantastic, thanks.
> Can you please add a version to the subject before sending the revised patches?
> Like "git format-patch --subject-prefix v4".
Sure, no problem. I'll start the next round at v4 unless you'd like some other starting
value :)
Thanks again for such valuable review Jan!
--Mark
>
> Thanks,
> -Jan
>
> -- >8 --
> Subject: [PATCH] Btrfs: improved readablity for add_inode_ref
>
> Moved part of the code into a sub function and replaced most of the gotos
> by ifs, hoping that it will be easier to read now.
>
> Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
> ---
> fs/btrfs/tree-log.c | 178 ++++++++++++++++++++++++++++-----------------------
> 1 files changed, 97 insertions(+), 81 deletions(-)
>
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index c86670f..59f3071 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -786,76 +786,18 @@ out:
> return match;
> }
>
> -
> -/*
> - * replay one inode back reference item found in the log tree.
> - * eb, slot and key refer to the buffer and key found in the log tree.
> - * root is the destination we are replaying into, and path is for temp
> - * use by this function. (it should be released on return).
> - */
> -static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
> +static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
> struct btrfs_root *root,
> - struct btrfs_root *log,
> struct btrfs_path *path,
> - struct extent_buffer *eb, int slot,
> - struct btrfs_key *key)
> + struct btrfs_root *log_root,
> + struct inode *dir, struct inode *inode,
> + struct btrfs_key *key,
> + struct extent_buffer *eb,
> + struct btrfs_inode_ref *ref,
> + char *name, int namelen, int *search_done)
> {
> - struct btrfs_inode_ref *ref;
> - struct btrfs_dir_item *di;
> - struct inode *dir;
> - struct inode *inode;
> - unsigned long ref_ptr;
> - unsigned long ref_end;
> - char *name;
> - int namelen;
> int ret;
> - int search_done = 0;
> -
> - /*
> - * it is possible that we didn't log all the parent directories
> - * for a given inode. If we don't find the dir, just don't
> - * copy the back ref in. The link count fixup code will take
> - * care of the rest
> - */
> - dir = read_one_inode(root, key->offset);
> - if (!dir)
> - return -ENOENT;
> -
> - inode = read_one_inode(root, key->objectid);
> - if (!inode) {
> - iput(dir);
> - return -EIO;
> - }
> -
> - ref_ptr = btrfs_item_ptr_offset(eb, slot);
> - ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
> -
> -again:
> - ref = (struct btrfs_inode_ref *)ref_ptr;
> -
> - namelen = btrfs_inode_ref_name_len(eb, ref);
> - name = kmalloc(namelen, GFP_NOFS);
> - BUG_ON(!name);
> -
> - read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
> -
> - /* if we already have a perfect match, we're done */
> - if (inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
> - btrfs_inode_ref_index(eb, ref),
> - name, namelen)) {
> - goto out;
> - }
> -
> - /*
> - * look for a conflicting back reference in the metadata.
> - * if we find one we have to unlink that name of the file
> - * before we add our new link. Later on, we overwrite any
> - * existing back reference, and we don't want to create
> - * dangling pointers in the directory.
> - */
> -
> - if (search_done)
> - goto insert;
> + struct btrfs_dir_item *di;
>
> ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
> if (ret == 0) {
> @@ -870,7 +812,7 @@ again:
> * if so, just jump out, we're done
> */
> if (key->objectid == key->offset)
> - goto out_nowrite;
> + return 1;
>
> /* check all the names in this back reference to see
> * if they are in the log. if so, we allow them to stay
> @@ -889,7 +831,7 @@ again:
> (unsigned long)(victim_ref + 1),
> victim_name_len);
>
> - if (!backref_in_log(log, key, victim_name,
> + if (!backref_in_log(log_root, key, victim_name,
> victim_name_len)) {
> btrfs_inc_nlink(inode);
> btrfs_release_path(path);
> @@ -908,7 +850,7 @@ again:
> * NOTE: we have searched root tree and checked the
> * coresponding ref, it does not need to check again.
> */
> - search_done = 1;
> + *search_done = 1;
> }
> btrfs_release_path(path);
>
> @@ -931,25 +873,99 @@ again:
> }
> btrfs_release_path(path);
>
> -insert:
> - /* insert our name */
> - ret = btrfs_add_link(trans, dir, inode, name, namelen, 0,
> - btrfs_inode_ref_index(eb, ref));
> - BUG_ON(ret);
> + return 0;
> +}
> +
> +/*
> + * replay one inode back reference item found in the log tree.
> + * eb, slot and key refer to the buffer and key found in the log tree.
> + * root is the destination we are replaying into, and path is for temp
> + * use by this function. (it should be released on return).
> + */
> +static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
> + struct btrfs_root *root,
> + struct btrfs_root *log,
> + struct btrfs_path *path,
> + struct extent_buffer *eb, int slot,
> + struct btrfs_key *key)
> +{
> + struct btrfs_inode_ref *ref;
> + struct inode *dir;
> + struct inode *inode;
> + unsigned long ref_ptr;
> + unsigned long ref_end;
> + char *name;
> + int namelen;
> + int ret;
> + int search_done = 0;
> +
> + /*
> + * it is possible that we didn't log all the parent directories
> + * for a given inode. If we don't find the dir, just don't
> + * copy the back ref in. The link count fixup code will take
> + * care of the rest
> + */
> + dir = read_one_inode(root, key->offset);
> + if (!dir)
> + return -ENOENT;
>
> - btrfs_update_inode(trans, root, inode);
> + inode = read_one_inode(root, key->objectid);
> + if (!inode) {
> + iput(dir);
> + return -EIO;
> + }
>
> -out:
> - ref_ptr = (unsigned long)(ref + 1) + namelen;
> - kfree(name);
> - if (ref_ptr < ref_end)
> - goto again;
> + ref_ptr = btrfs_item_ptr_offset(eb, slot);
> + ref_end = ref_ptr + btrfs_item_size_nr(eb, slot);
> +
> + while (ref_ptr < ref_end) {
> + ref = (struct btrfs_inode_ref *)ref_ptr;
> +
> + namelen = btrfs_inode_ref_name_len(eb, ref);
> + name = kmalloc(namelen, GFP_NOFS);
> + BUG_ON(!name);
> +
> + read_extent_buffer(eb, name, (unsigned long)(ref + 1), namelen);
> +
> + /* if we already have a perfect match, we're done */
> + if (!inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode),
> + btrfs_inode_ref_index(eb, ref),
> + name, namelen)) {
> + /*
> + * look for a conflicting back reference in the
> + * metadata. if we find one we have to unlink that name
> + * of the file before we add our new link. Later on, we
> + * overwrite any existing back reference, and we don't
> + * want to create dangling pointers in the directory.
> + */
> +
> + if (!search_done) {
> + ret = __add_inode_ref(trans, root, path, log,
> + dir, inode, key, eb, ref,
> + name, namelen,
> + &search_done);
> + if (ret == 1)
> + goto out;
> + BUG_ON(ret);
> + }
> +
> + /* insert our name */
> + ret = btrfs_add_link(trans, dir, inode, name, namelen,
> + 0, btrfs_inode_ref_index(eb, ref));
> + BUG_ON(ret);
> +
> + btrfs_update_inode(trans, root, inode);
> + }
> +
> + ref_ptr = (unsigned long)(ref + 1) + namelen;
> + kfree(name);
> + }
>
> /* finally write the back reference in the inode */
> ret = overwrite_item(trans, root, path, eb, slot, key);
> BUG_ON(ret);
>
> -out_nowrite:
> +out:
> btrfs_release_path(path);
> iput(dir);
> iput(inode);
> --
> 1.7.1
--
Mark Fasheh
next prev parent reply other threads:[~2012-08-15 17:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-08 18:55 [PATCH 0/3] btrfs: extended inode refs Mark Fasheh
2012-08-08 18:55 ` [PATCH 1/3] " Mark Fasheh
2012-08-14 9:32 ` Jan Schmidt
2012-08-14 16:51 ` Mark Fasheh
2012-08-08 18:55 ` [PATCH 2/3] " Mark Fasheh
2012-08-15 15:04 ` Jan Schmidt
2012-08-15 17:59 ` Mark Fasheh [this message]
2012-08-08 18:55 ` [PATCH 3/3] " Mark Fasheh
2012-08-15 8:46 ` Jan Schmidt
-- strict thread matches above, loose matches on Subject: below --
2012-05-21 21:46 [PATCH 0/3] " Mark Fasheh
2012-05-21 21:46 ` [PATCH 2/3] " Mark Fasheh
2012-07-06 14:57 ` Jan Schmidt
2012-08-06 23:31 ` Mark Fasheh
2012-04-05 20:09 [PATCH 0/3] " Mark Fasheh
2012-04-05 20:09 ` [PATCH 2/3] " Mark Fasheh
2012-04-12 13:08 ` Jan Schmidt
2012-05-03 23:12 ` Mark Fasheh
2012-05-04 11:39 ` David Sterba
2012-04-12 15:53 ` Jan Schmidt
2012-05-01 18:39 ` Mark Fasheh
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