Josef Bacik
2013-Jul-11 14:39 UTC
[PATCH] 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>
---
fs/btrfs/file.c | 62 +++++++++++++++++++++++++++++++++++-------------------
1 files changed, 40 insertions(+), 22 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 2d70849..dda2efb 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -595,20 +595,29 @@ 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;
@@ -619,8 +628,7 @@ 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;
@@ -629,18 +637,28 @@ 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);
--
1.7.7.6
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