diff options
| -rw-r--r-- | fs/btrfs/extent_map.c | 2 | ||||
| -rw-r--r-- | fs/btrfs/extent_map.h | 8 | ||||
| -rw-r--r-- | fs/btrfs/ioctl.c | 14 |
3 files changed, 24 insertions, 0 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 5a36add21305..c28ceddefae4 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -261,6 +261,7 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em) em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start; em->mod_start = merge->mod_start; em->generation = max(em->generation, merge->generation); + set_bit(EXTENT_FLAG_MERGED, &em->flags); rb_erase_cached(&merge->rb_node, &tree->map); RB_CLEAR_NODE(&merge->rb_node); @@ -278,6 +279,7 @@ static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em) RB_CLEAR_NODE(&merge->rb_node); em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start; em->generation = max(em->generation, merge->generation); + set_bit(EXTENT_FLAG_MERGED, &em->flags); free_extent_map(merge); } } diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h index 8e217337dff9..d2fa32ffe304 100644 --- a/fs/btrfs/extent_map.h +++ b/fs/btrfs/extent_map.h @@ -25,6 +25,8 @@ enum { EXTENT_FLAG_FILLING, /* filesystem extent mapping type */ EXTENT_FLAG_FS_MAPPING, + /* This em is merged from two or more physically adjacent ems */ + EXTENT_FLAG_MERGED, }; struct extent_map { @@ -40,6 +42,12 @@ struct extent_map { u64 ram_bytes; u64 block_start; u64 block_len; + + /* + * Generation of the extent map, for merged em it's the highest + * generation of all merged ems. + * For non-merged extents, it's from btrfs_file_extent_item::generation. + */ u64 generation; unsigned long flags; /* Used for chunk mappings, flag EXTENT_FLAG_FS_MAPPING must be set */ diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index ffebd420829e..1398d7b64c4e 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1175,6 +1175,20 @@ static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start, em = lookup_extent_mapping(em_tree, start, sectorsize); read_unlock(&em_tree->lock); + /* + * We can get a merged extent, in that case, we need to re-search + * tree to get the original em for defrag. + * + * If @newer_than is 0 or em::generation < newer_than, we can trust + * this em, as either we don't care about the generation, or the + * merged extent map will be rejected anyway. + */ + if (em && test_bit(EXTENT_FLAG_MERGED, &em->flags) && + newer_than && em->generation >= newer_than) { + free_extent_map(em); + em = NULL; + } + if (!em) { struct extent_state *cached = NULL; u64 end = start + sectorsize - 1; |