[PATCH 01/11] xfs: remove xfs_itruncate_data

* [PATCH 01/11] xfs: remove xfs_itruncate_data
  2011-12-08 15:57 [PATCH 00/11] inode shrink and misc updates Christoph Hellwig
@ 2011-12-08 15:57 ` Christoph Hellwig
  2011-12-13 21:23   ` Dave Chinner
  0 siblings, 1 reply; 32+ messages in thread
From: Christoph Hellwig @ 2011-12-08 15:57 UTC (permalink / raw)
  To: xfs

[-- Attachment #1: xfs-kill-xfs_itruncate_data --]
[-- Type: text/plain, Size: 14594 bytes --]

This wrapper isn't overly useful, not to say rather confusing.

Around the call to xfs_itruncate_extents it does:

 - add tracing
 - add a few asserts in debug builds
 - conditionally update the inode size in two places
 - log the inode

Both the tracing and the inode logging can be moved to xfs_itruncate_extents
as they are useful for the attribute fork as well - in fact the attr code
already does an equivalent xfs_trans_log_inode call just after calling
xfs_itruncate_extents.  The conditional size updates are a mess, and there
was no reason to do them in two places anyway, as the first one was
conditional on the inode having extents - but without extents we
xfs_itruncate_extents would be a no-op and the placement wouldn't matter
anyway.  Instead move the size assignments and the asserts that make sense
to the callers that want it.

As a side effect of this clean up xfs_setattr_size by introducing variables
for the old and new inode size, and moving the size updates into a common
place.

Signed-off-by: Christoph Hellwig <hch@lst.de>

---
 fs/xfs/xfs_attr.c        |    4 -
 fs/xfs/xfs_inode.c       |  124 +++--------------------------------------------
 fs/xfs/xfs_inode.h       |    2 
 fs/xfs/xfs_iops.c        |   47 +++++++++++------
 fs/xfs/xfs_qm_syscalls.c |    9 +++
 fs/xfs/xfs_trace.h       |    4 -
 fs/xfs/xfs_vnodeops.c    |   17 +++++-
 7 files changed, 65 insertions(+), 142 deletions(-)

Index: xfs/fs/xfs/xfs_attr.c
===================================================================

--- xfs.orig/fs/xfs/xfs_attr.c	2011-11-30 12:58:07.820044461 +0100
+++ xfs/fs/xfs/xfs_attr.c	2011-11-30 12:58:51.519807719 +0100
@@ -827,10 +827,6 @@ xfs_attr_inactive(xfs_inode_t *dp)
 	if (error)
 		goto out;
 
-	/*
-	 * Commit the last in the sequence of transactions.
-	 */
-	xfs_trans_log_inode(trans, dp, XFS_ILOG_CORE);
 	error = xfs_trans_commit(trans, XFS_TRANS_RELEASE_LOG_RES);
 	xfs_iunlock(dp, XFS_ILOCK_EXCL);
 
Index: xfs/fs/xfs/xfs_inode.c
===================================================================
--- xfs.orig/fs/xfs/xfs_inode.c	2011-11-30 12:58:07.830044408 +0100
+++ xfs/fs/xfs/xfs_inode.c	2011-11-30 12:58:51.519807719 +0100
@@ -1166,52 +1166,6 @@ xfs_ialloc(
 }
 
 /*
- * Check to make sure that there are no blocks allocated to the
- * file beyond the size of the file.  We don't check this for
- * files with fixed size extents or real time extents, but we
- * at least do it for regular files.
- */
-#ifdef DEBUG
-STATIC void
-xfs_isize_check(
-	struct xfs_inode	*ip,
-	xfs_fsize_t		isize)
-{
-	struct xfs_mount	*mp = ip->i_mount;
-	xfs_fileoff_t		map_first;
-	int			nimaps;
-	xfs_bmbt_irec_t		imaps[2];
-	int			error;
-
-	if (!S_ISREG(ip->i_d.di_mode))
-		return;
-
-	if (XFS_IS_REALTIME_INODE(ip))
-		return;
-
-	if (ip->i_d.di_flags & XFS_DIFLAG_EXTSIZE)
-		return;
-
-	nimaps = 2;
-	map_first = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
-	/*
-	 * The filesystem could be shutting down, so bmapi may return
-	 * an error.
-	 */
-	error = xfs_bmapi_read(ip, map_first,
-			 (XFS_B_TO_FSB(mp,
-			       (xfs_ufsize_t)XFS_MAXIOFFSET(mp)) - map_first),
-			 imaps, &nimaps, XFS_BMAPI_ENTIRE);
-	if (error)
-		return;
-	ASSERT(nimaps == 1);
-	ASSERT(imaps[0].br_startblock == HOLESTARTBLOCK);
-}
-#else	/* DEBUG */
-#define xfs_isize_check(ip, isize)
-#endif	/* DEBUG */
-
-/*
  * Free up the underlying blocks past new_size.  The new size must be smaller
  * than the current size.  This routine can be used both for the attribute and
  * data fork, and does not modify the inode size, which is left to the caller.
@@ -1258,6 +1212,8 @@ xfs_itruncate_extents(
 	ASSERT(ip->i_itemp->ili_lock_flags == 0);
 	ASSERT(!XFS_NOT_DQATTACHED(mp, ip));
 
+	trace_xfs_itruncate_extents_start(ip, new_size);
+
 	/*
 	 * Since it is possible for space to become allocated beyond
 	 * the end of the file (in a crash where the space is allocated
@@ -1325,6 +1281,14 @@ xfs_itruncate_extents(
 			goto out;
 	}
 
+	/*
+	 * Always re-log the inode so that our permanent transaction can keep
+	 * on rolling it forward in the log.
+	 */
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	trace_xfs_itruncate_extents_end(ip, new_size);
+
 out:
 	*tpp = tp;
 	return error;
@@ -1338,74 +1302,6 @@ out_bmap_cancel:
 	goto out;
 }
 
-int
-xfs_itruncate_data(
-	struct xfs_trans	**tpp,
-	struct xfs_inode	*ip,
-	xfs_fsize_t		new_size)
-{
-	int			error;
-
-	trace_xfs_itruncate_data_start(ip, new_size);
-
-	/*
-	 * The first thing we do is set the size to new_size permanently on
-	 * disk.  This way we don't have to worry about anyone ever being able
-	 * to look at the data being freed even in the face of a crash.
-	 * What we're getting around here is the case where we free a block, it
-	 * is allocated to another file, it is written to, and then we crash.
-	 * If the new data gets written to the file but the log buffers
-	 * containing the free and reallocation don't, then we'd end up with
-	 * garbage in the blocks being freed.  As long as we make the new_size
-	 * permanent before actually freeing any blocks it doesn't matter if
-	 * they get written to.
-	 */
-	if (ip->i_d.di_nextents > 0) {
-		/*
-		 * If we are not changing the file size then do not update
-		 * the on-disk file size - we may be called from
-		 * xfs_inactive_free_eofblocks().  If we update the on-disk
-		 * file size and then the system crashes before the contents
-		 * of the file are flushed to disk then the files may be
-		 * full of holes (ie NULL files bug).
-		 */
-		if (ip->i_size != new_size) {
-			ip->i_d.di_size = new_size;
-			ip->i_size = new_size;
-			xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
-		}
-	}
-
-	error = xfs_itruncate_extents(tpp, ip, XFS_DATA_FORK, new_size);
-	if (error)
-		return error;
-
-	/*
-	 * If we are not changing the file size then do not update the on-disk
-	 * file size - we may be called from xfs_inactive_free_eofblocks().
-	 * If we update the on-disk file size and then the system crashes
-	 * before the contents of the file are flushed to disk then the files
-	 * may be full of holes (ie NULL files bug).
-	 */
-	xfs_isize_check(ip, new_size);
-	if (ip->i_size != new_size) {
-		ip->i_d.di_size = new_size;
-		ip->i_size = new_size;
-	}
-
-	ASSERT(new_size != 0 || ip->i_delayed_blks == 0);
-	ASSERT(new_size != 0 || ip->i_d.di_nextents == 0);
-
-	/*
-	 * Always re-log the inode so that our permanent transaction can keep
-	 * on rolling it forward in the log.
-	 */
-	xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE);
-
-	trace_xfs_itruncate_data_end(ip, new_size);
-	return 0;
-}
-
 /*
  * This is called when the inode's link count goes to 0.
  * We place the on-disk inode on a list in the AGI.  It
Index: xfs/fs/xfs/xfs_inode.h
===================================================================
--- xfs.orig/fs/xfs/xfs_inode.h	2011-11-30 12:58:08.843372251 +0100
+++ xfs/fs/xfs/xfs_inode.h	2011-11-30 12:58:51.523141034 +0100
@@ -491,8 +491,6 @@ int		xfs_ifree(struct xfs_trans *, xfs_i
 			   struct xfs_bmap_free *);
 int		xfs_itruncate_extents(struct xfs_trans **, struct xfs_inode *,
 				      int, xfs_fsize_t);
-int		xfs_itruncate_data(struct xfs_trans **, struct xfs_inode *,
-				   xfs_fsize_t);
 int		xfs_iunlink(struct xfs_trans *, xfs_inode_t *);
 
 void		xfs_iext_realloc(xfs_inode_t *, int, int);
Index: xfs/fs/xfs/xfs_iops.c
===================================================================
--- xfs.orig/fs/xfs/xfs_iops.c	2011-11-30 12:58:07.856710929 +0100
+++ xfs/fs/xfs/xfs_iops.c	2011-11-30 12:58:51.523141034 +0100
@@ -750,6 +750,7 @@ xfs_setattr_size(
 	struct xfs_mount	*mp = ip->i_mount;
 	struct inode		*inode = VFS_I(ip);
 	int			mask = iattr->ia_valid;
+	xfs_off_t		oldsize, newsize;
 	struct xfs_trans	*tp;
 	int			error;
 	uint			lock_flags;
@@ -777,11 +778,13 @@ xfs_setattr_size(
 		lock_flags |= XFS_IOLOCK_EXCL;
 	xfs_ilock(ip, lock_flags);
 
+	oldsize = ip->i_size;
+	newsize = iattr->ia_size;
+
 	/*
 	 * Short circuit the truncate case for zero length files.
 	 */
-	if (iattr->ia_size == 0 &&
-	    ip->i_size == 0 && ip->i_d.di_nextents == 0) {
+	if (newsize == 0 && oldsize == 0 && ip->i_d.di_nextents == 0) {
 		if (!(mask & (ATTR_CTIME|ATTR_MTIME)))
 			goto out_unlock;
 
@@ -807,14 +810,14 @@ xfs_setattr_size(
 	 * the inode to the transaction, because the inode cannot be unlocked
 	 * once it is a part of the transaction.
 	 */
-	if (iattr->ia_size > ip->i_size) {
+	if (newsize > oldsize) {
 		/*
 		 * Do the first part of growing a file: zero any data in the
 		 * last block that is beyond the old EOF.  We need to do this
 		 * before the inode is joined to the transaction to modify
 		 * i_size.
 		 */
-		error = xfs_zero_eof(ip, iattr->ia_size, ip->i_size);
+		error = xfs_zero_eof(ip, newsize, oldsize);
 		if (error)
 			goto out_unlock;
 	}
@@ -833,8 +836,8 @@ xfs_setattr_size(
 	 * here and prevents waiting for other data not within the range we
 	 * care about here.
 	 */
-	if (ip->i_size != ip->i_d.di_size && iattr->ia_size > ip->i_d.di_size) {
-		error = xfs_flush_pages(ip, ip->i_d.di_size, iattr->ia_size, 0,
+	if (oldsize != ip->i_d.di_size && newsize > ip->i_d.di_size) {
+		error = xfs_flush_pages(ip, ip->i_d.di_size, newsize, 0,
 					FI_NONE);
 		if (error)
 			goto out_unlock;
@@ -845,8 +848,7 @@ xfs_setattr_size(
 	 */
 	inode_dio_wait(inode);
 
-	error = -block_truncate_page(inode->i_mapping, iattr->ia_size,
-				     xfs_get_blocks);
+	error = -block_truncate_page(inode->i_mapping, newsize, xfs_get_blocks);
 	if (error)
 		goto out_unlock;
 
@@ -857,7 +859,7 @@ xfs_setattr_size(
 	if (error)
 		goto out_trans_cancel;
 
-	truncate_setsize(inode, iattr->ia_size);
+	truncate_setsize(inode, newsize);
 
 	commit_flags = XFS_TRANS_RELEASE_LOG_RES;
 	lock_flags |= XFS_ILOCK_EXCL;
@@ -876,19 +878,30 @@ xfs_setattr_size(
 	 * these flags set.  For all other operations the VFS set these flags
 	 * explicitly if it wants a timestamp update.
 	 */
-	if (iattr->ia_size != ip->i_size &&
-	    (!(mask & (ATTR_CTIME | ATTR_MTIME)))) {
+	if (newsize != oldsize && (!(mask & (ATTR_CTIME | ATTR_MTIME)))) {
 		iattr->ia_ctime = iattr->ia_mtime =
 			current_fs_time(inode->i_sb);
 		mask |= ATTR_CTIME | ATTR_MTIME;
 	}
 
-	if (iattr->ia_size > ip->i_size) {
-		ip->i_d.di_size = iattr->ia_size;
-		ip->i_size = iattr->ia_size;
-	} else if (iattr->ia_size <= ip->i_size ||
-		   (iattr->ia_size == 0 && ip->i_d.di_nextents)) {
-		error = xfs_itruncate_data(&tp, ip, iattr->ia_size);
+	/*
+	 * The first thing we do is set the size to new_size permanently on
+	 * disk.  This way we don't have to worry about anyone ever being able
+	 * to look at the data being freed even in the face of a crash.
+	 * What we're getting around here is the case where we free a block, it
+	 * is allocated to another file, it is written to, and then we crash.
+	 * If the new data gets written to the file but the log buffers
+	 * containing the free and reallocation don't, then we'd end up with
+	 * garbage in the blocks being freed.  As long as we make the new size
+	 * permanent before actually freeing any blocks it doesn't matter if
+	 * they get written to.
+	 */
+	ip->i_d.di_size = newsize;
+	ip->i_size = newsize;
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	if (newsize <= oldsize) {
+		error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, newsize);
 		if (error)
 			goto out_trans_abort;
 
Index: xfs/fs/xfs/xfs_qm_syscalls.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm_syscalls.c	2011-11-30 12:58:07.866710876 +0100
+++ xfs/fs/xfs/xfs_qm_syscalls.c	2011-11-30 12:58:51.523141034 +0100
@@ -31,6 +31,7 @@
 #include "xfs_mount.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_inode.h"
+#include "xfs_inode_item.h"
 #include "xfs_itable.h"
 #include "xfs_bmap.h"
 #include "xfs_rtalloc.h"
@@ -263,13 +264,19 @@ xfs_qm_scall_trunc_qfile(
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, 0);
 
-	error = xfs_itruncate_data(&tp, ip, 0);
+	ip->i_d.di_size = 0;
+	ip->i_size = 0;
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+	error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, 0);
 	if (error) {
 		xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES |
 				     XFS_TRANS_ABORT);
 		goto out_unlock;
 	}
 
+	ASSERT(ip->i_d.di_nextents == 0);
+
 	xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 
Index: xfs/fs/xfs/xfs_trace.h
===================================================================
--- xfs.orig/fs/xfs/xfs_trace.h	2011-11-30 12:58:07.876710822 +0100
+++ xfs/fs/xfs/xfs_trace.h	2011-11-30 12:58:51.523141034 +0100
@@ -1090,8 +1090,8 @@ DECLARE_EVENT_CLASS(xfs_itrunc_class,
 DEFINE_EVENT(xfs_itrunc_class, name, \
 	TP_PROTO(struct xfs_inode *ip, xfs_fsize_t new_size), \
 	TP_ARGS(ip, new_size))
-DEFINE_ITRUNC_EVENT(xfs_itruncate_data_start);
-DEFINE_ITRUNC_EVENT(xfs_itruncate_data_end);
+DEFINE_ITRUNC_EVENT(xfs_itruncate_extents_start);
+DEFINE_ITRUNC_EVENT(xfs_itruncate_extents_end);
 
 TRACE_EVENT(xfs_pagecache_inval,
 	TP_PROTO(struct xfs_inode *ip, xfs_off_t start, xfs_off_t finish),
Index: xfs/fs/xfs/xfs_vnodeops.c
===================================================================
--- xfs.orig/fs/xfs/xfs_vnodeops.c	2011-11-30 12:58:07.893377397 +0100
+++ xfs/fs/xfs/xfs_vnodeops.c	2011-11-30 12:58:51.526474350 +0100
@@ -226,7 +226,14 @@ xfs_free_eofblocks(
 		xfs_ilock(ip, XFS_ILOCK_EXCL);
 		xfs_trans_ijoin(tp, ip, 0);
 
-		error = xfs_itruncate_data(&tp, ip, ip->i_size);
+		/*
+		 * Do not update the on-disk file size.  If we update the
+		 * on-disk file size and then the system crashes before the
+		 * contents of the file are flushed to disk then the files
+		 * may be full of holes (ie NULL files bug).
+		 */
+		error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK,
+					      ip->i_size);
 		if (error) {
 			/*
 			 * If we get an error at this point we simply don't
@@ -670,13 +677,19 @@ xfs_inactive(
 		xfs_ilock(ip, XFS_ILOCK_EXCL);
 		xfs_trans_ijoin(tp, ip, 0);
 
-		error = xfs_itruncate_data(&tp, ip, 0);
+		ip->i_d.di_size = 0;
+		ip->i_size = 0;
+		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+		error = xfs_itruncate_extents(&tp, ip, XFS_DATA_FORK, 0);
 		if (error) {
 			xfs_trans_cancel(tp,
 				XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
 			xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
 			return VN_INACTIVE_CACHE;
 		}
+
+		ASSERT(ip->i_d.di_nextents == 0);
 	} else if (S_ISLNK(ip->i_d.di_mode)) {
 
 		/*

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