Messages in this thread Patch in this message | | | From | Daeho Jeong <> | Subject | [PATCH] f2fs: remove race condition in releasing cblocks | Date | Fri, 8 May 2020 13:25:06 +0900 |
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From: Daeho Jeong <daehojeong@google.com>
Now, if writing pages and releasing compress blocks occur simultaneously, and releasing cblocks is executed more than one time to a file, then total block count of filesystem and block count of the file could be incorrect and damaged.
We have to execute releasing compress blocks only one time for a file without being interfered by writepages path.
Signed-off-by: Daeho Jeong <daehojeong@google.com> --- fs/f2fs/file.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 4aab4b42d8ba..a92bc51b9b28 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -3488,6 +3488,7 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg) pgoff_t page_idx = 0, last_idx; unsigned int released_blocks = 0; int ret; + int writecount; if (!f2fs_sb_has_compression(F2FS_I_SB(inode))) return -EOPNOTSUPP; @@ -3509,13 +3510,29 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg) inode_lock(inode); - if (!IS_IMMUTABLE(inode)) { - F2FS_I(inode)->i_flags |= F2FS_IMMUTABLE_FL; - f2fs_set_inode_flags(inode); - inode->i_ctime = current_time(inode); - f2fs_mark_inode_dirty_sync(inode, true); + writecount = atomic_read(&inode->i_writecount); + if ((filp->f_mode & FMODE_WRITE && writecount != 1) || writecount) { + ret = -EBUSY; + goto out; } + if (IS_IMMUTABLE(inode)) { + ret = -EINVAL; + goto out; + } + + ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX); + if (ret) + goto out; + + if (!F2FS_I(inode)->i_compr_blocks) + goto out; + + F2FS_I(inode)->i_flags |= F2FS_IMMUTABLE_FL; + f2fs_set_inode_flags(inode); + inode->i_ctime = current_time(inode); + f2fs_mark_inode_dirty_sync(inode, true); + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); down_write(&F2FS_I(inode)->i_mmap_sem); @@ -3554,9 +3571,9 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg) up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); up_write(&F2FS_I(inode)->i_mmap_sem); - - inode_unlock(inode); out: + inode_unlock(inode); + mnt_drop_write_file(filp); if (ret >= 0) { -- 2.26.2.526.g744177e7f7-goog
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