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authorMark Fasheh <mfasheh@suse.de>2013-08-06 11:42:50 -0700
committerChris Mason <chris.mason@fusionio.com>2013-09-01 08:04:59 -0400
commit4b384318a74e38eb248f74f9a92a700d2ce841f1 (patch)
tree5ef01855a2824b7c832e9303a19cfb2527c9d08d /fs/btrfs/compression.c
parent32b7c687c52a0b78a7d41ce6423c2fd8f5ca92da (diff)
btrfs: Introduce extent_read_full_page_nolock()
We want this for btrfs_extent_same. Basically readpage and friends do their own extent locking but for the purposes of dedupe, we want to have both files locked down across a set of readpage operations (so that we can compare data). Introduce this variant and a flag which can be set for extent_read_full_page() to indicate that we are already locked. Partial credit for this patch goes to Gabriel de Perthuis <g2p.code@gmail.com> as I have included a fix from him to the original patch which avoids a deadlock on compressed extents. Signed-off-by: Mark Fasheh <mfasheh@suse.de> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/compression.c')
-rw-r--r--fs/btrfs/compression.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index b189bd1e7a3..37dff5b2d56 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -639,7 +639,11 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
faili = nr_pages - 1;
cb->nr_pages = nr_pages;
- add_ra_bio_pages(inode, em_start + em_len, cb);
+ /* In the parent-locked case, we only locked the range we are
+ * interested in. In all other cases, we can opportunistically
+ * cache decompressed data that goes beyond the requested range. */
+ if (!(bio_flags & EXTENT_BIO_PARENT_LOCKED))
+ add_ra_bio_pages(inode, em_start + em_len, cb);
/* include any pages we added in add_ra-bio_pages */
uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;