xfs
[Top] [All Lists]

[PATCH 2/2] xfs_fsr: create extent-based attr to grow forkoff

To: xfs-oss <xfs@xxxxxxxxxxx>
Subject: [PATCH 2/2] xfs_fsr: create extent-based attr to grow forkoff
From: Eric Sandeen <sandeen@xxxxxxxxxx>
Date: Fri, 30 Mar 2012 10:01:45 -0500
Cc: Gabriel VLASIU <gabriel@xxxxxxxxxx>
In-reply-to: <4F75C939.6030009@xxxxxxxxxx>
References: <4F75C939.6030009@xxxxxxxxxx>
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:11.0) Gecko/20120327 Thunderbird/11.0.1
In some cases the target file may have a non-local attribute,
but the temp file gets assigned a local attribute on creation,
due to selinux, for example.

In this case, the large-ish selinux attr will create a forkoff
in the temp file smaller than the forkoff in the target file,
because the FMT_EXTENTS attr takes up less space.  There is
no mechanism to grow the forkoff to match, so we can end up
failing to swap these 2 inodes if the result is not enough
data space in the temp inode as a result.

After testing the target file for a non-local extent, and
checking to see if the forkoff needs to be grown on the first
pass, we can add a large attr to knock all attributes of the
temp file out of local format, and grow the fork offset.

This passes xfstest 227, and also resolves issues seen on
a metadata image provided by Gabriel.

Reported-by: Gabriel VLASIU <gabriel@xxxxxxxxxx>
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---

diff --git a/fsr/xfs_fsr.c b/fsr/xfs_fsr.c
index d83bdc9..e8ab028 100644
--- a/fsr/xfs_fsr.c
+++ b/fsr/xfs_fsr.c
@@ -1022,6 +1022,8 @@ fsr_setup_attr_fork(
        struct stat64   tstatbuf;
        int             i;
        int             diff = 0;
+       struct fsxattr  fsx;
+       int             target_attr_local = 0;
        int             last_forkoff = 0;
        int             no_change_cnt = 0;
        int             ret;
@@ -1052,6 +1054,11 @@ fsr_setup_attr_fork(
                return -1;
        }
 
+       memset(&fsx, 0, sizeof(fsx));
+       ioctl(fd, XFS_IOC_FSGETXATTR, &fsx);
+       if (fsx.fsx_nextents == 0)
+               target_attr_local = 1;
+
        i = 0;
        do {
                xfs_bstat_t     tbstat;
@@ -1072,6 +1079,7 @@ fsr_setup_attr_fork(
                if (dflag)
                        fsrprintf(_("orig forkoff %d, temp forkoff %d\n"),
                                        bstatp->bs_forkoff, tbstat.bs_forkoff);
+               diff = tbstat.bs_forkoff - bstatp->bs_forkoff;
 
                snprintf(name, sizeof(name), "user.%d", i);
 
@@ -1086,6 +1094,21 @@ fsr_setup_attr_fork(
                                return -1;
                        }
                        continue;
+               } else if (i == 0 && diff < 0 && target_attr_local == 0) {
+                       /*
+                        * A small attr may exist from eg selinux but, if the
+                        * target is not local, write a big attr to tempfile
+                        * to knock it out of local format to match target.
+                        * This should actually increase the temp forkoffset.
+                        */
+                       char val[2048];
+                       memset(val, 'X', 2048);
+                       ret = fsetxattr(tfd, name, val, 2048, XATTR_CREATE);
+                       if (ret) {
+                               fsrprintf(_("could not set large ATTR\n"));
+                               return -1;
+                       }
+                       continue;
                }
 
                /*
@@ -1100,7 +1123,6 @@ fsr_setup_attr_fork(
                last_forkoff = tbstat.bs_forkoff;
 
                /* work out which way to grow the fork */
-               diff = tbstat.bs_forkoff - bstatp->bs_forkoff;
                if (abs(diff) > fsgeom.inodesize - sizeof(struct xfs_dinode)) {
                        fsrprintf(_("forkoff diff %d too large!\n"), diff);
                        return -1;

<Prev in Thread] Current Thread [Next in Thread>