From 71dfd5a396d11512aa6c8ed0d35b268bc084bb9b Mon Sep 17 00:00:00 2001 From: Lachlan McIlroy Date: Tue, 8 May 2007 13:50:12 +1000 Subject: [PATCH] [XFS] Fix race in xfs_write() b/w dmapi callout and direct I/O checks. In xfs_write() the iolock is dropped and reacquired in XFS_SEND_DATA() which means that the file could change from not-cached to cached and we need to redo the direct I/O checks. We should also redo the direct I/O checks when the file size changes regardless if O_APPEND is set or not. SGI-PV: 963483 SGI-Modid: xfs-linux-melb:xfs-kern:28440a Signed-off-by: Lachlan McIlroy Signed-off-by: David Chinner Signed-off-by: Tim Shimmin --- fs/xfs/linux-2.6/xfs_lrw.c | 57 +++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 29 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_lrw.c b/fs/xfs/linux-2.6/xfs_lrw.c index 82ab792c7fc9..b2a1beb33888 100644 --- a/fs/xfs/linux-2.6/xfs_lrw.c +++ b/fs/xfs/linux-2.6/xfs_lrw.c @@ -724,6 +724,34 @@ start: goto out_unlock_mutex; } + if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) && + !(ioflags & IO_INVIS) && !eventsent)) { + int dmflags = FILP_DELAY_FLAG(file); + + if (need_i_mutex) + dmflags |= DM_FLAGS_IMUX; + + xfs_iunlock(xip, XFS_ILOCK_EXCL); + error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp, + pos, count, + dmflags, &locktype); + if (error) { + goto out_unlock_internal; + } + xfs_ilock(xip, XFS_ILOCK_EXCL); + eventsent = 1; + + /* + * The iolock was dropped and reacquired in XFS_SEND_DATA + * so we have to recheck the size when appending. + * We will only "goto start;" once, since having sent the + * event prevents another call to XFS_SEND_DATA, which is + * what allows the size to change in the first place. + */ + if ((file->f_flags & O_APPEND) && pos != xip->i_size) + goto start; + } + if (ioflags & IO_ISDIRECT) { xfs_buftarg_t *target = (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ? @@ -749,35 +777,6 @@ start: if (new_size > xip->i_size) io->io_new_size = new_size; - if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) && - !(ioflags & IO_INVIS) && !eventsent)) { - loff_t savedsize = pos; - int dmflags = FILP_DELAY_FLAG(file); - - if (need_i_mutex) - dmflags |= DM_FLAGS_IMUX; - - xfs_iunlock(xip, XFS_ILOCK_EXCL); - error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp, - pos, count, - dmflags, &locktype); - if (error) { - goto out_unlock_internal; - } - xfs_ilock(xip, XFS_ILOCK_EXCL); - eventsent = 1; - - /* - * The iolock was dropped and reacquired in XFS_SEND_DATA - * so we have to recheck the size when appending. - * We will only "goto start;" once, since having sent the - * event prevents another call to XFS_SEND_DATA, which is - * what allows the size to change in the first place. - */ - if ((file->f_flags & O_APPEND) && savedsize != xip->i_size) - goto start; - } - if (likely(!(ioflags & IO_INVIS))) { file_update_time(file); xfs_ichgtime_fast(xip, inode,