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c278531d39
BUG #1) All places where we call ext4_flush_completed_IO are broken because buffered io and DIO/AIO goes through three stages 1) submitted io, 2) completed io (in i_completed_io_list) conversion pended 3) finished io (conversion done) And by calling ext4_flush_completed_IO we will flush only requests which were in (2) stage, which is wrong because: 1) punch_hole and truncate _must_ wait for all outstanding unwritten io regardless to it's state. 2) fsync and nolock_dio_read should also wait because there is a time window between end_page_writeback() and ext4_add_complete_io() As result integrity fsync is broken in case of buffered write to fallocated region: fsync blkdev_completion ->filemap_write_and_wait_range ->ext4_end_bio ->end_page_writeback <-- filemap_write_and_wait_range return ->ext4_flush_completed_IO sees empty i_completed_io_list but pended conversion still exist ->ext4_add_complete_io BUG #2) Race window becomes wider due to the 'ext4: completed_io locking cleanup V4' patch series This patch make following changes: 1) ext4_flush_completed_io() now first try to flush completed io and when wait for any outstanding unwritten io via ext4_unwritten_wait() 2) Rename function to more appropriate name. 3) Assert that all callers of ext4_flush_unwritten_io should hold i_mutex to prevent endless wait Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> |
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.. | ||
acl.c | ||
acl.h | ||
balloc.c | ||
bitmap.c | ||
block_validity.c | ||
dir.c | ||
ext4_extents.h | ||
ext4_jbd2.c | ||
ext4_jbd2.h | ||
ext4.h | ||
extents.c | ||
file.c | ||
fsync.c | ||
hash.c | ||
ialloc.c | ||
indirect.c | ||
inode.c | ||
ioctl.c | ||
Kconfig | ||
Makefile | ||
mballoc.c | ||
mballoc.h | ||
migrate.c | ||
mmp.c | ||
move_extent.c | ||
namei.c | ||
page-io.c | ||
resize.c | ||
super.c | ||
symlink.c | ||
truncate.h | ||
xattr_security.c | ||
xattr_trusted.c | ||
xattr_user.c | ||
xattr.c | ||
xattr.h |