6.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Qu Wenruo wqu@suse.com
[ Upstream commit ecde48a1a6b3256bd49db8780bf37556b157783c ]
The address space flag AS_STABLE_WRITES determine if FGP_STABLE for will wait for the folio to finish its writeback.
For btrfs, due to the default data checksum behavior, if we modify the folio while it's still under writeback, it will cause data checksum mismatch. Thus for quite some call sites we manually call folio_wait_writeback() to prevent such problem from happening.
Currently there is only one call site inside btrfs really utilizing FGP_STABLE, and in that case we also manually call folio_wait_writeback() to do the waiting.
But it's better to properly expose the stable writes flag to a per-inode basis, to allow call sites to fully benefit from FGP_STABLE flag. E.g. for inodes with NODATASUM allowing beginning dirtying the page without waiting for writeback.
This involves:
- Update the mapping's stable write flag when setting/clearing NODATASUM inode flag using ioctl This only works for empty files, so it should be fine.
- Update the mapping's stable write flag when reading an inode from disk
- Remove the explicit folio_wait_writeback() for FGP_BEGINWRITE call site
Signed-off-by: Qu Wenruo wqu@suse.com Signed-off-by: David Sterba dsterba@suse.com Stable-dep-of: 48c1d1bb525b ("btrfs: fix the inode leak in btrfs_iget()") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/btrfs_inode.h | 8 ++++++++ fs/btrfs/file.c | 1 - fs/btrfs/inode.c | 2 ++ fs/btrfs/ioctl.c | 1 + 4 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index b2fa33911c280..029fba82b81da 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -516,6 +516,14 @@ static inline void btrfs_assert_inode_locked(struct btrfs_inode *inode) lockdep_assert_held(&inode->vfs_inode.i_rwsem); }
+static inline void btrfs_update_inode_mapping_flags(struct btrfs_inode *inode) +{ + if (inode->flags & BTRFS_INODE_NODATASUM) + mapping_clear_stable_writes(inode->vfs_inode.i_mapping); + else + mapping_set_stable_writes(inode->vfs_inode.i_mapping); +} + /* Array of bytes with variable length, hexadecimal format 0x1234 */ #define CSUM_FMT "0x%*phN" #define CSUM_FMT_VALUE(size, bytes) size, bytes diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index a92997a583bd2..cd4e40a719186 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -874,7 +874,6 @@ static noinline int prepare_one_folio(struct inode *inode, struct folio **folio_ ret = PTR_ERR(folio); return ret; } - folio_wait_writeback(folio); /* Only support page sized folio yet. */ ASSERT(folio_order(folio) == 0); ret = set_folio_extent_mapped(folio); diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 0db50d19b9a1f..90782fd9f37b8 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -3925,6 +3925,7 @@ static int btrfs_read_locked_inode(struct inode *inode, struct btrfs_path *path)
btrfs_inode_split_flags(btrfs_inode_flags(leaf, inode_item), &BTRFS_I(inode)->flags, &BTRFS_I(inode)->ro_flags); + btrfs_update_inode_mapping_flags(BTRFS_I(inode));
cache_index: /* @@ -6340,6 +6341,7 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans, if (btrfs_test_opt(fs_info, NODATACOW)) BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW | BTRFS_INODE_NODATASUM; + btrfs_update_inode_mapping_flags(BTRFS_I(inode)); }
ret = btrfs_insert_inode_locked(inode); diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index e666c141cae0b..10a97f0af8d4b 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -393,6 +393,7 @@ int btrfs_fileattr_set(struct mnt_idmap *idmap,
update_flags: binode->flags = binode_flags; + btrfs_update_inode_mapping_flags(binode); btrfs_sync_inode_flags_to_i_flags(inode); inode_inc_iversion(inode); inode_set_ctime_current(inode);