diff options
author | Chris Mason <chris.mason@oracle.com> | 2008-11-07 17:35:44 (GMT) |
---|---|---|
committer | Chris Mason <chris.mason@oracle.com> | 2008-11-07 17:35:44 (GMT) |
commit | af09abfece59aa50bfbf16f6f1f85822554e061f (patch) | |
tree | ca419511219b433a2bf45626814777df8667a19f /fs/btrfs/compression.c | |
parent | 4366211ccd050e00674b3276b5ed81981b2d7793 (diff) | |
download | linux-fsl-qoriq-af09abfece59aa50bfbf16f6f1f85822554e061f.tar.xz |
Btrfs: make sure compressed bios don't complete too soon
When writing a compressed extent, a number of bios are created that
point to a single struct compressed_bio. At end_io time an atomic counter in
the compressed_bio struct makes sure that all of the bios have finished
before final end_io processing is done.
But when multiple bios are needed to write a compressed extent, the
counter was being incremented after the first bio was sent to submit_bio.
It is possible the bio will complete before the counter is incremented,
making the end_io handler free the compressed_bio struct before
processing is finished.
The fix is to increment the atomic counter before bio submission,
both for compressed reads and writes.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/compression.c')
-rw-r--r-- | fs/btrfs/compression.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 284f210..7397c62 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -314,6 +314,13 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start, PAGE_CACHE_SIZE) { bio_get(bio); + /* + * inc the count before we submit the bio so + * we know the end IO handler won't happen before + * we inc the count. Otherwise, the cb might get + * freed before we're done setting it up + */ + atomic_inc(&cb->pending_bios); ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); BUG_ON(ret); @@ -323,7 +330,6 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start, bio_put(bio); bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); - atomic_inc(&cb->pending_bios); bio->bi_private = cb; bio->bi_end_io = end_compressed_bio_write; bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); @@ -573,6 +579,14 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); BUG_ON(ret); + /* + * inc the count before we submit the bio so + * we know the end IO handler won't happen before + * we inc the count. Otherwise, the cb might get + * freed before we're done setting it up + */ + atomic_inc(&cb->pending_bios); + ret = btrfs_map_bio(root, READ, comp_bio, 0, 0); BUG_ON(ret); @@ -580,7 +594,6 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); - atomic_inc(&cb->pending_bios); comp_bio->bi_private = cb; comp_bio->bi_end_io = end_compressed_bio_read; |