From: Daeho Jeong daehojeong@google.com
[ Upstream commit a46bebd502fe1a3bd1d22f64cedd93e7e7702693 ]
To fix a race condition between atomic write aborts, I use the inode lock and make COW inode to be re-usable thoroughout the whole atomic file inode lifetime.
Reported-by: syzbot+823000d23b3400619f7c@syzkaller.appspotmail.com Fixes: 3db1de0e582c ("f2fs: change the current atomic write way") Signed-off-by: Daeho Jeong daehojeong@google.com Reviewed-by: Chao Yu chao@kernel.org Signed-off-by: Jaegeuk Kim jaegeuk@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/f2fs/file.c | 44 +++++++++++++++++++++++++++++--------------- fs/f2fs/inode.c | 11 +++++++++-- fs/f2fs/segment.c | 3 --- fs/f2fs/super.c | 2 -- 4 files changed, 38 insertions(+), 22 deletions(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 8583c098bc985..05297427552ac 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1867,7 +1867,10 @@ static int f2fs_release_file(struct inode *inode, struct file *filp) atomic_read(&inode->i_writecount) != 1) return 0;
+ inode_lock(inode); f2fs_abort_atomic_write(inode, true); + inode_unlock(inode); + return 0; }
@@ -1882,8 +1885,12 @@ static int f2fs_file_flush(struct file *file, fl_owner_t id) * before dropping file lock, it needs to do in ->flush. */ if (F2FS_I(inode)->atomic_write_task == current && - (current->flags & PF_EXITING)) + (current->flags & PF_EXITING)) { + inode_lock(inode); f2fs_abort_atomic_write(inode, true); + inode_unlock(inode); + } + return 0; }
@@ -2089,19 +2096,28 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate) goto out; }
- /* Create a COW inode for atomic write */ - pinode = f2fs_iget(inode->i_sb, fi->i_pino); - if (IS_ERR(pinode)) { - f2fs_up_write(&fi->i_gc_rwsem[WRITE]); - ret = PTR_ERR(pinode); - goto out; - } + /* Check if the inode already has a COW inode */ + if (fi->cow_inode == NULL) { + /* Create a COW inode for atomic write */ + pinode = f2fs_iget(inode->i_sb, fi->i_pino); + if (IS_ERR(pinode)) { + f2fs_up_write(&fi->i_gc_rwsem[WRITE]); + ret = PTR_ERR(pinode); + goto out; + }
- ret = f2fs_get_tmpfile(mnt_userns, pinode, &fi->cow_inode); - iput(pinode); - if (ret) { - f2fs_up_write(&fi->i_gc_rwsem[WRITE]); - goto out; + ret = f2fs_get_tmpfile(mnt_userns, pinode, &fi->cow_inode); + iput(pinode); + if (ret) { + f2fs_up_write(&fi->i_gc_rwsem[WRITE]); + goto out; + } + + set_inode_flag(fi->cow_inode, FI_COW_FILE); + clear_inode_flag(fi->cow_inode, FI_INLINE_DATA); + } else { + /* Reuse the already created COW inode */ + f2fs_do_truncate_blocks(fi->cow_inode, 0, true); }
f2fs_write_inode(inode, NULL); @@ -2109,8 +2125,6 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate) stat_inc_atomic_inode(inode);
set_inode_flag(inode, FI_ATOMIC_FILE); - set_inode_flag(fi->cow_inode, FI_COW_FILE); - clear_inode_flag(fi->cow_inode, FI_INLINE_DATA);
isize = i_size_read(inode); fi->original_i_size = isize; diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 622eb7963afac..f438f39ae3f3e 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -767,11 +767,18 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc) void f2fs_evict_inode(struct inode *inode) { struct f2fs_sb_info *sbi = F2FS_I_SB(inode); - nid_t xnid = F2FS_I(inode)->i_xattr_nid; + struct f2fs_inode_info *fi = F2FS_I(inode); + nid_t xnid = fi->i_xattr_nid; int err = 0;
f2fs_abort_atomic_write(inode, true);
+ if (fi->cow_inode) { + clear_inode_flag(fi->cow_inode, FI_COW_FILE); + iput(fi->cow_inode); + fi->cow_inode = NULL; + } + trace_f2fs_evict_inode(inode); truncate_inode_pages_final(&inode->i_data);
@@ -858,7 +865,7 @@ void f2fs_evict_inode(struct inode *inode) stat_dec_inline_inode(inode); stat_dec_compr_inode(inode); stat_sub_compr_blocks(inode, - atomic_read(&F2FS_I(inode)->i_compr_blocks)); + atomic_read(&fi->i_compr_blocks));
if (likely(!f2fs_cp_error(sbi) && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 06cae55265841..269f89d202c61 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -192,9 +192,6 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean) if (!f2fs_is_atomic_file(inode)) return;
- clear_inode_flag(fi->cow_inode, FI_COW_FILE); - iput(fi->cow_inode); - fi->cow_inode = NULL; release_atomic_write_cnt(inode); clear_inode_flag(inode, FI_ATOMIC_COMMITTED); clear_inode_flag(inode, FI_ATOMIC_REPLACE); diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 53878feb69d33..551468dad3275 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1430,8 +1430,6 @@ static int f2fs_drop_inode(struct inode *inode) atomic_inc(&inode->i_count); spin_unlock(&inode->i_lock);
- f2fs_abort_atomic_write(inode, true); - /* should remain fi->extent_tree for writepage */ f2fs_destroy_extent_node(inode);