fi->i_flags can be read by f2fs_update_inode() in the writeback path,
f2fs_getattr(), and f2fs_fileattr_get() without holding inode_lock or
fi->i_sem, while it can be concurrently written by
f2fs_setflags_common(), set_compress_context(), and
f2fs_disable_compressed_file() under inode_lock and/or fi->i_sem.
This is a data race as defined by the LKMM. Use READ_ONCE() on the
read side and WRITE_ONCE() on the write side to ensure proper marking
of the concurrent accesses.
Fixes: 19f99cee206c ("f2fs: add core inode operations")
Cc: [email protected]
Signed-off-by: Cen Zhang <[email protected]>
---
fs/f2fs/f2fs.h | 4 ++--
fs/f2fs/file.c | 6 +++---
fs/f2fs/inode.c | 2 +-
3 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c66472e409a3..28161df79e4f 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4764,7 +4764,7 @@ static inline int set_compress_context(struct inode
*inode)
fi->i_compress_algorithm == COMPRESS_ZSTD) &&
F2FS_OPTION(sbi).compress_level)
fi->i_compress_level = F2FS_OPTION(sbi).compress_level;
- fi->i_flags |= F2FS_COMPR_FL;
+ WRITE_ONCE(fi->i_flags, READ_ONCE(fi->i_flags) | F2FS_COMPR_FL);
set_inode_flag(inode, FI_COMPRESSED_FILE);
stat_inc_compr_inode(inode);
inc_compr_inode_stat(inode);
@@ -4791,7 +4791,7 @@ static inline bool f2fs_disable_compressed_file(struct
inode *inode)
return false;
}
- fi->i_flags &= ~F2FS_COMPR_FL;
+ WRITE_ONCE(fi->i_flags, READ_ONCE(fi->i_flags) & ~F2FS_COMPR_FL);
stat_dec_compr_inode(inode);
clear_inode_flag(inode, FI_COMPRESSED_FILE);
f2fs_mark_inode_dirty_sync(inode, true);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index c8a2f17a8f11..abff927a8699 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1005,7 +1005,7 @@ int f2fs_getattr(struct mnt_idmap *idmap, const struct
path *path,
}
}
- flags = fi->i_flags;
+ flags = READ_ONCE(fi->i_flags);
if (flags & F2FS_COMPR_FL)
stat->attributes |= STATX_ATTR_COMPRESSED;
if (flags & F2FS_APPEND_FL)
@@ -2153,7 +2153,7 @@ static int f2fs_setflags_common(struct inode *inode, u32
iflags, u32 mask)
}
}
- fi->i_flags = iflags | (fi->i_flags & ~mask);
+ WRITE_ONCE(fi->i_flags, iflags | (READ_ONCE(fi->i_flags) & ~mask));
f2fs_bug_on(F2FS_I_SB(inode), (fi->i_flags & F2FS_COMPR_FL) &&
(fi->i_flags & F2FS_NOCOMP_FL));
@@ -3437,7 +3437,7 @@ int f2fs_fileattr_get(struct dentry *dentry, struct
file_kattr *fa)
{
struct inode *inode = d_inode(dentry);
struct f2fs_inode_info *fi = F2FS_I(inode);
- u32 fsflags = f2fs_iflags_to_fsflags(fi->i_flags);
+ u32 fsflags = f2fs_iflags_to_fsflags(READ_ONCE(fi->i_flags));
if (IS_ENCRYPTED(inode))
fsflags |= FS_ENCRYPT_FL;
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 078874db918c..17c8aff690fb 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -720,7 +720,7 @@ void f2fs_update_inode(struct inode *inode, struct folio
*node_folio)
else if (S_ISREG(inode->i_mode))
ri->i_gc_failures = cpu_to_le16(fi->i_gc_failures);
ri->i_xattr_nid = cpu_to_le32(fi->i_xattr_nid);
- ri->i_flags = cpu_to_le32(fi->i_flags);
+ ri->i_flags = cpu_to_le32(READ_ONCE(fi->i_flags));
ri->i_pino = cpu_to_le32(fi->i_pino);
ri->i_generation = cpu_to_le32(inode->i_generation);
ri->i_dir_level = fi->i_dir_level;
--
2.34.1
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