From: Filipe Manana fdmanana@suse.com
[ Upstream commit e4cc1483f35940c9288c332dd275f6fad485f8d2 ]
At btrfs_drop_extent_map_range() we are clearing the EXTENT_FLAG_LOGGING bit on a 'flags' variable that was not initialized. This makes static checkers complain about it, so initialize the 'flags' variable before clearing the bit.
In practice this has no consequences, because EXTENT_FLAG_LOGGING should not be set when btrfs_drop_extent_map_range() is called, as an fsync locks the inode in exclusive mode, locks the inode's mmap semaphore in exclusive mode too and it always flushes all delalloc.
Also add a comment about why we clear EXTENT_FLAG_LOGGING on a copy of the flags of the split extent map.
Reported-by: Dan Carpenter error27@gmail.com Link: https://lore.kernel.org/linux-btrfs/Y%2FyipSVozUDEZKow@kili/ Fixes: db21370bffbc ("btrfs: drop extent map range more efficiently") Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/extent_map.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 6092a4eedc923..b8ae02aa632e3 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -760,7 +760,13 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end, goto next; }
+ flags = em->flags; clear_bit(EXTENT_FLAG_PINNED, &em->flags); + /* + * In case we split the extent map, we want to preserve the + * EXTENT_FLAG_LOGGING flag on our extent map, but we don't want + * it on the new extent maps. + */ clear_bit(EXTENT_FLAG_LOGGING, &flags); modified = !list_empty(&em->list);
@@ -771,7 +777,6 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end, if (em->start >= start && em_end <= end) goto remove_em;
- flags = em->flags; gen = em->generation; compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);