Commit 21b32e6a authored by Amir Goldstein's avatar Amir Goldstein Committed by Christian Brauner
Browse files

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: default avatarAmir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231122122715.2561213-17-amir73il@gmail.com


Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 3d5cd491

include/linux/fs.h

+26 −0
Original line number Diff line number Diff line
@@ -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