redonkable/alistair23-linux
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xfs: fix incorrect remote symlink block count

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When CRCs are enabled, the number of blocks needed to hold a remote
symlink on a 1k block size filesystem may be 2 instead of 1. The
transaction reservation for the allocated blocks was not taking this
into account and only allocating one block. Hence when trying to
read or invalidate such symlinks, we are mapping a hole where there
should be a block and things go bad at that point.

Fix the reservation to use the correct block count, clean up the
block count calculation similar to the remote attribute calculation,
and add a debug guard to detect when we don't write the entire
symlink to disk.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
This commit is contained in:
Dave Chinner 2013-05-27 16:38:20 +10:00 committed by Ben Myers
parent 34510185ab
commit 321a95839e
1 changed files with 6 additions and 14 deletions
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20
fs/xfs/xfs_symlink.c
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@ -56,16 +56,9 @@ xfs_symlink_blocks(
struct xfs_mount *mp,
int pathlen)
{
int fsblocks = 0;
int len = pathlen;
int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
do {
fsblocks++;
len -= XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
} while (len > 0);
ASSERT(fsblocks <= XFS_SYMLINK_MAPS);
return fsblocks;
return (pathlen + buflen - 1) / buflen;
}
static int
@ -405,7 +398,7 @@ xfs_symlink(
if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
fs_blocks = 0;
else
fs_blocks = XFS_B_TO_FSB(mp, pathlen);
fs_blocks = xfs_symlink_blocks(mp, pathlen);
resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
error = xfs_trans_reserve(tp, resblks, XFS_SYMLINK_LOG_RES(mp), 0,
XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
@ -512,7 +505,7 @@ xfs_symlink(
cur_chunk = target_path;
offset = 0;
for (n = 0; n < nmaps; n++) {
char *buf;
char *buf;
d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
@ -525,9 +518,7 @@ xfs_symlink(
bp->b_ops = &xfs_symlink_buf_ops;
byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
if (pathlen < byte_cnt) {
byte_cnt = pathlen;
}
byte_cnt = min(byte_cnt, pathlen);
buf = bp->b_addr;
buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
@ -542,6 +533,7 @@ xfs_symlink(
xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
(char *)bp->b_addr);
}
ASSERT(pathlen == 0);
}
/*