From 21b32e6a0ab5b174fa1ca2fb4c212577cf405d83 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 22 Nov 2023 14:27:15 +0200 Subject: fs: create {sb,file}_write_not_started() helpers Create new helpers {sb,file}_write_not_started() that can be used to assert that sb_start_write() is not held. This is needed for fanotify "pre content" events. Signed-off-by: Amir Goldstein Link: https://lore.kernel.org/r/20231122122715.2561213-17-amir73il@gmail.com Reviewed-by: Josef Bacik Signed-off-by: Christian Brauner --- include/linux/fs.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 75a10b632edd..ae0e2fb7bcea 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1670,6 +1670,17 @@ static inline bool sb_write_started(const struct super_block *sb) return __sb_write_started(sb, SB_FREEZE_WRITE); } +/** + * sb_write_not_started - check if SB_FREEZE_WRITE is not held + * @sb: the super we write to + * + * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN. + */ +static inline bool sb_write_not_started(const struct super_block *sb) +{ + return __sb_write_started(sb, SB_FREEZE_WRITE) <= 0; +} + /** * file_write_started - check if SB_FREEZE_WRITE is held * @file: the file we write to @@ -1685,6 +1696,21 @@ static inline bool file_write_started(const struct file *file) return sb_write_started(file_inode(file)->i_sb); } +/** + * file_write_not_started - check if SB_FREEZE_WRITE is not held + * @file: the file we write to + * + * May be false positive with !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN. + * May be false positive with !S_ISREG, because file_start_write() has + * no effect on !S_ISREG. + */ +static inline bool file_write_not_started(const struct file *file) +{ + if (!S_ISREG(file_inode(file)->i_mode)) + return true; + return sb_write_not_started(file_inode(file)->i_sb); +} + /** * sb_end_write - drop write access to a superblock * @sb: the super we wrote to -- cgit