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authorJosef Bacik <jbacik@fusionio.com>2013-07-11 10:34:59 -0400
committerChris Mason <chris.mason@fusionio.com>2013-08-09 19:30:09 -0400
commitee20a98314e52a6675e94d1a07ca205ffdf09a72 (patch)
tree7a4b93b7c6b3603795a36464944d8c479806e41c
parented8c4913da4951957bf8afc788522788881ff405 (diff)
downloadlinux-ee20a98314e52a6675e94d1a07ca205ffdf09a72.tar.bz2
Btrfs: allow splitting of hole em's when dropping extent cache
I noticed while running multi-threaded fsync tests that sometimes fsck would complain about an improper gap. This happens because we fail to add a hole extent to the file, which was happening when we'd split a hole EM because btrfs_drop_extent_cache was just discarding the whole em instead of splitting it. So this patch fixes this by allowing us to split a hole em properly, which means that added holes actually get logged properly and we no longer see this fsck error. Thankfully we're tolerant of these sort of problems so a user would not see any adverse effects of this bug, other than fsck complaining. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
-rw-r--r--fs/btrfs/file.c62
1 files changed, 40 insertions, 22 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a005fe2c072a..8e686a427ce2 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -596,20 +596,29 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
if (no_splits)
goto next;
- if (em->block_start < EXTENT_MAP_LAST_BYTE &&
- em->start < start) {
+ if (em->start < start) {
split->start = em->start;
split->len = start - em->start;
- split->orig_start = em->orig_start;
- split->block_start = em->block_start;
- if (compressed)
- split->block_len = em->block_len;
- else
- split->block_len = split->len;
- split->ram_bytes = em->ram_bytes;
- split->orig_block_len = max(split->block_len,
- em->orig_block_len);
+ if (em->block_start < EXTENT_MAP_LAST_BYTE) {
+ split->orig_start = em->orig_start;
+ split->block_start = em->block_start;
+
+ if (compressed)
+ split->block_len = em->block_len;
+ else
+ split->block_len = split->len;
+ split->orig_block_len = max(split->block_len,
+ em->orig_block_len);
+ split->ram_bytes = em->ram_bytes;
+ } else {
+ split->orig_start = split->start;
+ split->block_len = 0;
+ split->block_start = em->block_start;
+ split->orig_block_len = 0;
+ split->ram_bytes = split->len;
+ }
+
split->generation = gen;
split->bdev = em->bdev;
split->flags = flags;
@@ -620,8 +629,7 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
split = split2;
split2 = NULL;
}
- if (em->block_start < EXTENT_MAP_LAST_BYTE &&
- testend && em->start + em->len > start + len) {
+ if (testend && em->start + em->len > start + len) {
u64 diff = start + len - em->start;
split->start = start + len;
@@ -630,18 +638,28 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
split->flags = flags;
split->compress_type = em->compress_type;
split->generation = gen;
- split->orig_block_len = max(em->block_len,
+
+ if (em->block_start < EXTENT_MAP_LAST_BYTE) {
+ split->orig_block_len = max(em->block_len,
em->orig_block_len);
- split->ram_bytes = em->ram_bytes;
- if (compressed) {
- split->block_len = em->block_len;
- split->block_start = em->block_start;
- split->orig_start = em->orig_start;
+ split->ram_bytes = em->ram_bytes;
+ if (compressed) {
+ split->block_len = em->block_len;
+ split->block_start = em->block_start;
+ split->orig_start = em->orig_start;
+ } else {
+ split->block_len = split->len;
+ split->block_start = em->block_start
+ + diff;
+ split->orig_start = em->orig_start;
+ }
} else {
- split->block_len = split->len;
- split->block_start = em->block_start + diff;
- split->orig_start = em->orig_start;
+ split->ram_bytes = split->len;
+ split->orig_start = split->start;
+ split->block_len = 0;
+ split->block_start = em->block_start;
+ split->orig_block_len = 0;
}
ret = add_extent_mapping(em_tree, split, modified);