ext4: fix races between changing inode journal mode and ext4_writepages
In ext4, there is a race condition between changing inode journal mode and ext4_writepages(). While ext4_writepages() is executed on a non-journalled mode inode, the inode's journal mode could be enabled by ioctl() and then, some pages dirtied after switching the journal mode will be still exposed to ext4_writepages() in non-journaled mode. To resolve this problem, we use fs-wide per-cpu rw semaphore by Jan Kara's suggestion because we don't want to waste ext4_inode_info's space for this extra rare case. Signed-off-by:Daeho Jeong <daeho.jeong@samsung.com> Signed-off-by:
Theodore Ts'o <tytso@mit.edu> Reviewed-by:
Jan Kara <jack@suse.cz>
parent
4c546592
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