Btrfs: ensure tmpfile inode is always persisted with link count of 0
If we open a file with O_TMPFILE, don't do any further operation on
it (so that the inode item isn't updated) and then force a transaction
commit, we get a persisted inode item with a link count of 1, and not 0
as it should be.
Steps to reproduce it (requires a modern xfs_io with -T support):
$ mkfs.btrfs -f /dev/sdd
$ mount -o /dev/sdd /mnt
$ xfs_io -T /mnt &
$ sync
Then btrfs-debug-tree shows the inode item with a link count of 1:
$ btrfs-debug-tree /dev/sdd
(...)
fs tree key (FS_TREE ROOT_ITEM 0)
leaf 29556736 items 4 free space 15851 generation 6 owner 5
fs uuid f164d01b-1b92-481d-a4e4-435fb0f843d0
chunk uuid 0e3d0e56-bcca-4a1c-aa5f-cec2c6f4f7a6
item 0 key (256 INODE_ITEM 0) itemoff 16123 itemsize 160
inode generation 3 transid 6 size 0 block group 0 mode 40755 links 1
item 1 key (256 INODE_REF 256) itemoff 16111 itemsize 12
inode ref index 0 namelen 2 name: ..
item 2 key (257 INODE_ITEM 0) itemoff 15951 itemsize 160
inode generation 6 transid 6 size 0 block group 0 mode 100600 links 1
item 3 key (ORPHAN ORPHAN_ITEM 257) itemoff 15951 itemsize 0
orphan item
checksum tree key (CSUM_TREE ROOT_ITEM 0)
(...)
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
1 file changed