From 7d4fb40ad7efe4586d1341d4731377fb4530836f Mon Sep 17 00:00:00 2001 From: Nathan Scott Date: Fri, 9 Jun 2006 15:27:16 +1000 Subject: [XFS] Start writeout earlier (on last close) in the case where we have a truncate down followed by delayed allocation (buffered writes) - worst case scenario for the notorious NULL files problem. This reduces the window where we are exposed to that problem significantly. SGI-PV: 917976 SGI-Modid: xfs-linux-melb:xfs-kern:26100a Signed-off-by: Nathan Scott --- fs/xfs/xfs_vnodeops.c | 88 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 52 insertions(+), 36 deletions(-) (limited to 'fs/xfs/xfs_vnodeops.c') diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c index cb36a56392e..35906bae92e 100644 --- a/fs/xfs/xfs_vnodeops.c +++ b/fs/xfs/xfs_vnodeops.c @@ -16,8 +16,6 @@ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ -#include - #include "xfs.h" #include "xfs_fs.h" #include "xfs_types.h" @@ -58,32 +56,14 @@ #include "xfs_log_priv.h" #include "xfs_mac.h" - -/* - * The maximum pathlen is 1024 bytes. Since the minimum file system - * blocksize is 512 bytes, we can get a max of 2 extents back from - * bmapi. - */ -#define SYMLINK_MAPS 2 - -/* - * For xfs, we check that the file isn't too big to be opened by this kernel. - * No other open action is required for regular files. Devices are handled - * through the specfs file system, pipes through fifofs. Device and - * fifo vnodes are "wrapped" by specfs and fifofs vnodes, respectively, - * when a new vnode is first looked up or created. - */ STATIC int xfs_open( bhv_desc_t *bdp, cred_t *credp) { int mode; - vnode_t *vp; - xfs_inode_t *ip; - - vp = BHV_TO_VNODE(bdp); - ip = XFS_BHVTOI(bdp); + vnode_t *vp = BHV_TO_VNODE(bdp); + xfs_inode_t *ip = XFS_BHVTOI(bdp); if (XFS_FORCED_SHUTDOWN(ip->i_mount)) return XFS_ERROR(EIO); @@ -101,6 +81,36 @@ xfs_open( return 0; } +STATIC int +xfs_close( + bhv_desc_t *bdp, + int flags, + lastclose_t lastclose, + cred_t *credp) +{ + vnode_t *vp = BHV_TO_VNODE(bdp); + xfs_inode_t *ip = XFS_BHVTOI(bdp); + int error = 0; + + if (XFS_FORCED_SHUTDOWN(ip->i_mount)) + return XFS_ERROR(EIO); + + if (lastclose != L_TRUE || !VN_ISREG(vp)) + return 0; + + /* + * If we previously truncated this file and removed old data in + * the process, we want to initiate "early" writeout on the last + * close. This is an attempt to combat the notorious NULL files + * problem which is particularly noticable from a truncate down, + * buffered (re-)write (delalloc), followed by a crash. What we + * are effectively doing here is significantly reducing the time + * window where we'd otherwise be exposed to that problem. + */ + if (VUNTRUNCATE(vp) && VN_DIRTY(vp) && ip->i_delayed_blks > 0) + VOP_FLUSH_PAGES(vp, 0, -1, XFS_B_ASYNC, FI_NONE, error); + return error; +} /* * xfs_getattr @@ -665,9 +675,17 @@ xfs_setattr( ((ip->i_d.di_nlink != 0 || !(mp->m_flags & XFS_MOUNT_WSYNC)) ? 1 : 0)); - if (code) { + if (code) goto abort_return; - } + /* + * Truncated "down", so we're removing references + * to old data here - if we now delay flushing for + * a long time, we expose ourselves unduly to the + * notorious NULL files problem. So, we mark this + * vnode and flush it when the file is closed, and + * do not wait the usual (long) time for writeout. + */ + VTRUNCATE(vp); } /* * Have to do this even if the file's size doesn't change. @@ -936,6 +954,13 @@ xfs_access( } +/* + * The maximum pathlen is 1024 bytes. Since the minimum file system + * blocksize is 512 bytes, we can get a max of 2 extents back from + * bmapi. + */ +#define SYMLINK_MAPS 2 + /* * xfs_readlink * @@ -1470,9 +1495,6 @@ xfs_inactive_symlink_local( return 0; } -/* - * - */ STATIC int xfs_inactive_attrs( xfs_inode_t *ip, @@ -1531,10 +1553,10 @@ xfs_release( vp = BHV_TO_VNODE(bdp); ip = XFS_BHVTOI(bdp); + mp = ip->i_mount; - if (!VN_ISREG(vp) || (ip->i_d.di_mode == 0)) { + if (!VN_ISREG(vp) || (ip->i_d.di_mode == 0)) return 0; - } /* If this is a read-only mount, don't do this (would generate I/O) */ if (vp->v_vfsp->vfs_flag & VFS_RDONLY) @@ -1546,8 +1568,6 @@ xfs_release( return 0; #endif - mp = ip->i_mount; - if (ip->i_d.di_nlink != 0) { if ((((ip->i_d.di_mode & S_IFMT) == S_IFREG) && ((ip->i_d.di_size > 0) || (VN_CACHED(vp) > 0 || @@ -3745,7 +3765,6 @@ xfs_inode_flush( return error; } - int xfs_set_dmattrs ( bhv_desc_t *bdp, @@ -3786,10 +3805,6 @@ xfs_set_dmattrs ( return error; } - -/* - * xfs_reclaim - */ STATIC int xfs_reclaim( bhv_desc_t *bdp) @@ -4645,6 +4660,7 @@ xfs_change_file_space( vnodeops_t xfs_vnodeops = { BHV_IDENTITY_INIT(VN_BHV_XFS,VNODE_POSITION_XFS), .vop_open = xfs_open, + .vop_close = xfs_close, .vop_read = xfs_read, #ifdef HAVE_SENDFILE .vop_sendfile = xfs_sendfile, -- cgit v1.2.3-70-g09d2