[XFS] Fix callers of xfs_iozero() to zero the correct range.

The problem is the two callers of xfs_iozero() are rounding out the range
to be zeroed to the end of a fsb and in some cases this extends past the
new eof. The call to commit_write() in xfs_iozero() will cause the Linux
inode's file size to be set too high.

SGI-PV: 960788
SGI-Modid: xfs-linux-melb:xfs-kern:28013a

Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

2 files changed, 19 insertions, 19 deletions

diff --git a/fs/xfs/linux-2.6/xfs_lrw.c b/fs/xfs/linux-2.6/xfs_lrw.c
index 65e79b471d49..50ba4794f19f 100644
--- a/fs/xfs/linux-2.6/xfs_lrw.c
+++ b/fs/xfs/linux-2.6/xfs_lrw.c
@@ -134,8 +134,7 @@ STATIC int
 xfs_iozero(
         struct inode            *ip,    /* inode                        */
         loff_t                  pos,    /* offset in file               */
-        size_t                  count,  /* size of data to zero         */
-        loff_t                  end_size)       /* max file size to set */
+        size_t                  count)  /* size of data to zero         */
 {
         unsigned                bytes;
         struct page             *page;
@@ -172,8 +171,6 @@ xfs_iozero(
                 if (!status) {
                         pos += bytes;
                         count -= bytes;
-                        if (pos > i_size_read(ip))
-                                i_size_write(ip, pos < end_size ? pos : end_size);
                 }
 
 unlock:
@@ -449,8 +446,8 @@ STATIC int				/* error (positive) */
 xfs_zero_last_block(
         struct inode    *ip,
         xfs_iocore_t    *io,
-        xfs_fsize_t     isize,
-        xfs_fsize_t     end_size)
+        xfs_fsize_t     offset,
+        xfs_fsize_t     isize)
 {
         xfs_fileoff_t   last_fsb;
         xfs_mount_t     *mp = io->io_mount;
@@ -459,7 +456,6 @@ xfs_zero_last_block(
         int             zero_len;
         int             error = 0;
         xfs_bmbt_irec_t imap;
-        loff_t          loff;
 
         ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
 
@@ -494,9 +490,10 @@ xfs_zero_last_block(
          */
         XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
 
-        loff = XFS_FSB_TO_B(mp, last_fsb);
         zero_len = mp->m_sb.sb_blocksize - zero_offset;
-        error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
+        if (isize + zero_len > offset)
+                zero_len = offset - isize;
+        error = xfs_iozero(ip, isize, zero_len);
 
         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
         ASSERT(error >= 0);
@@ -519,14 +516,15 @@ xfs_zero_eof(
         bhv_vnode_t     *vp,
         xfs_iocore_t    *io,
         xfs_off_t       offset,         /* starting I/O offset */
-        xfs_fsize_t     isize,          /* current inode size */
-        xfs_fsize_t     end_size)       /* terminal inode size */
+        xfs_fsize_t     isize)          /* current inode size */
 {
         struct inode    *ip = vn_to_inode(vp);
         xfs_fileoff_t   start_zero_fsb;
         xfs_fileoff_t   end_zero_fsb;
         xfs_fileoff_t   zero_count_fsb;
         xfs_fileoff_t   last_fsb;
+        xfs_fileoff_t   zero_off;
+        xfs_fsize_t     zero_len;
         xfs_mount_t     *mp = io->io_mount;
         int             nimaps;
         int             error = 0;
@@ -540,7 +538,7 @@ xfs_zero_eof(
          * First handle zeroing the block on which isize resides.
          * We only zero a part of that block so it is handled specially.
          */
-        error = xfs_zero_last_block(ip, io, isize, end_size);
+        error = xfs_zero_last_block(ip, io, offset, isize);
         if (error) {
                 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
                 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
@@ -601,10 +599,13 @@ xfs_zero_eof(
                  */
                 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
 
-                error = xfs_iozero(ip,
-                                   XFS_FSB_TO_B(mp, start_zero_fsb),
-                                   XFS_FSB_TO_B(mp, imap.br_blockcount),
-                                   end_size);
+                zero_off = XFS_FSB_TO_B(mp, start_zero_fsb);
+                zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount);
+
+                if ((zero_off + zero_len) > offset)
+                        zero_len = offset - zero_off;
+
+                error = xfs_iozero(ip, zero_off, zero_len);
                 if (error) {
                         goto out_lock;
                 }
@@ -783,8 +784,7 @@ start:
          */
 
         if (pos > isize) {
-                error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
-                                        isize, pos + count);
+                error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos, isize);
                 if (error) {
                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
                         goto out_unlock_mutex;
diff --git a/fs/xfs/linux-2.6/xfs_lrw.h b/fs/xfs/linux-2.6/xfs_lrw.h
index c77e62efb742..7ac51b1d2161 100644
--- a/fs/xfs/linux-2.6/xfs_lrw.h
+++ b/fs/xfs/linux-2.6/xfs_lrw.h
@@ -83,7 +83,7 @@ extern int xfs_bdstrat_cb(struct xfs_buf *);
 extern int xfs_dev_is_read_only(struct xfs_mount *, char *);
 
 extern int xfs_zero_eof(struct bhv_vnode *, struct xfs_iocore *, xfs_off_t,
-                                xfs_fsize_t, xfs_fsize_t);
+                                xfs_fsize_t);
 extern ssize_t xfs_read(struct bhv_desc *, struct kiocb *,
                                 const struct iovec *, unsigned int,
                                 loff_t *, int, struct cred *);