diff options
| author | Jan Schmidt <list.btrfs@jan-o-sch.net> | 2012-04-13 12:28:08 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.cz> | 2012-04-18 19:22:23 +0200 |
| commit | b916a59adfdc875381b68ced258694b434cf43ae (patch) | |
| tree | 7c73c9326cd558e9a5ae34381a6450e354a65a9d /fs/btrfs | |
| parent | aefc1eb13ebbb86c5ffade8a9e2425cd71032d7e (diff) | |
Btrfs: add missing read locks in backref.c
iref_to_path and iterate_irefs both increment the eb's refcount to use it
after releasing the path. Both depend on consistent data remaining in the
extent buffer and need a read lock to protect it.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/backref.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index fb56bcc80377..bcec06750232 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -22,6 +22,7 @@ #include "ulist.h" #include "transaction.h" #include "delayed-ref.h" +#include "locking.h" /* * this structure records all encountered refs on the way up to the root @@ -893,18 +894,22 @@ static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, s64 bytes_left = size - 1; struct extent_buffer *eb = eb_in; struct btrfs_key found_key; + int leave_spinning = path->leave_spinning; if (bytes_left >= 0) dest[bytes_left] = '\0'; + path->leave_spinning = 1; while (1) { len = btrfs_inode_ref_name_len(eb, iref); bytes_left -= len; if (bytes_left >= 0) read_extent_buffer(eb, dest + bytes_left, (unsigned long)(iref + 1), len); - if (eb != eb_in) + if (eb != eb_in) { + btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); + } ret = inode_ref_info(parent, 0, fs_root, path, &found_key); if (ret > 0) ret = -ENOENT; @@ -919,8 +924,11 @@ static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, slot = path->slots[0]; eb = path->nodes[0]; /* make sure we can use eb after releasing the path */ - if (eb != eb_in) + if (eb != eb_in) { atomic_inc(&eb->refs); + btrfs_tree_read_lock(eb); + btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); + } btrfs_release_path(path); iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); @@ -931,6 +939,7 @@ static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, } btrfs_release_path(path); + path->leave_spinning = leave_spinning; if (ret) return ERR_PTR(ret); @@ -1260,6 +1269,7 @@ static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, struct btrfs_key found_key; while (!ret) { + path->leave_spinning = 1; ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, &found_key); if (ret < 0) @@ -1275,6 +1285,8 @@ static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, eb = path->nodes[0]; /* make sure we can use eb after releasing the path */ atomic_inc(&eb->refs); + btrfs_tree_read_lock(eb); + btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); btrfs_release_path(path); item = btrfs_item_nr(eb, slot); @@ -1293,6 +1305,7 @@ static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, len = sizeof(*iref) + name_len; iref = (struct btrfs_inode_ref *)((char *)iref + len); } + btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); } |