xfs: xfs_attr_inactive leaves inconsistent attr fork state behind

commit 6dfe5a049f2d48582050339d2a6b6fda36dfd14c upstream.

xfs_attr_inactive() is supposed to clean up the attribute fork when
the inode is being freed. While it removes attribute fork extents,
it completely ignores attributes in local format, which means that
there can still be active attributes on the inode after
xfs_attr_inactive() has run.

This leads to problems with concurrent inode writeback - the in-core
inode attribute fork is removed without locking on the assumption
that nothing will be attempting to access the attribute fork after a
call to xfs_attr_inactive() because it isn't supposed to exist on
disk any more.

To fix this, make xfs_attr_inactive() completely remove all traces
of the attribute fork from the inode, regardless of it's state.
Further, also remove the in-core attribute fork structure safely so
that there is nothing further that needs to be done by callers to
clean up the attribute fork. This means we can remove the in-core
and on-disk attribute forks atomically.

Also, on error simply remove the in-memory attribute fork. There's
nothing that can be done with it once we have failed to remove the
on-disk attribute fork, so we may as well just blow it away here
anyway.

Reported-by: Waiman Long <waiman.long@hp.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 15105dbc9e28dbd92a80b851e90a79a5f2bb453c..0166e7e829a770eed653913bf6ca4c86b5bc4d85 100644 (file)
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -498,8 +498,8 @@ xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
  * After the last attribute is removed revert to original inode format,
  * making all literal area available to the data fork once more.
  */
-STATIC void
-xfs_attr_fork_reset(
+void
+xfs_attr_fork_remove(
        struct xfs_inode        *ip,
        struct xfs_trans        *tp)
 {
@@ -565,7 +565,7 @@ xfs_attr_shortform_remove(xfs_da_args_t *args)
            (mp->m_flags & XFS_MOUNT_ATTR2) &&
            (dp->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
            !(args->op_flags & XFS_DA_OP_ADDNAME)) {
-               xfs_attr_fork_reset(dp, args->trans);
+               xfs_attr_fork_remove(dp, args->trans);
        } else {
                xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
                dp->i_d.di_forkoff = xfs_attr_shortform_bytesfit(dp, totsize);
@@ -828,7 +828,7 @@ xfs_attr3_leaf_to_shortform(
        if (forkoff == -1) {
                ASSERT(dp->i_mount->m_flags & XFS_MOUNT_ATTR2);
                ASSERT(dp->i_d.di_format != XFS_DINODE_FMT_BTREE);
-               xfs_attr_fork_reset(dp, args->trans);
+               xfs_attr_fork_remove(dp, args->trans);
                goto out;
        }
 

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h b/fs/xfs/libxfs/xfs_attr_leaf.h
index e2929da7c3ba40c1156bfcfe762f2f076389e64f..4f3a60aa93d4de8a73fd2cc813fcb96a2b4752f8 100644 (file)
--- a/fs/xfs/libxfs/xfs_attr_leaf.h
+++ b/fs/xfs/libxfs/xfs_attr_leaf.h
@@ -53,7 +53,7 @@ int   xfs_attr_shortform_remove(struct xfs_da_args *args);
 int    xfs_attr_shortform_list(struct xfs_attr_list_context *context);
 int    xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
 int    xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes);
-
+void   xfs_attr_fork_remove(struct xfs_inode *ip, struct xfs_trans *tp);
 
 /*
  * Internal routines when attribute fork size == XFS_LBSIZE(mp).

diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
index 83af4c14963579b3a8377e43c54e4cd0825ca236..487c8374a1e0da41dbb4d926485cb6f869467061 100644 (file)
--- a/fs/xfs/xfs_attr_inactive.c
+++ b/fs/xfs/xfs_attr_inactive.c
@@ -379,23 +379,31 @@ xfs_attr3_root_inactive(
        return error;
 }
 
+/*
+ * xfs_attr_inactive kills all traces of an attribute fork on an inode. It
+ * removes both the on-disk and in-memory inode fork. Note that this also has to
+ * handle the condition of inodes without attributes but with an attribute fork
+ * configured, so we can't use xfs_inode_hasattr() here.
+ *
+ * The in-memory attribute fork is removed even on error.
+ */
 int
-xfs_attr_inactive(xfs_inode_t *dp)
+xfs_attr_inactive(
+       struct xfs_inode        *dp)
 {
-       xfs_trans_t *trans;
-       xfs_mount_t *mp;
-       int error;
+       struct xfs_trans        *trans;
+       struct xfs_mount        *mp;
+       int                     cancel_flags = 0;
+       int                     lock_mode = XFS_ILOCK_SHARED;
+       int                     error = 0;
 
        mp = dp->i_mount;
        ASSERT(! XFS_NOT_DQATTACHED(mp, dp));
 
-       xfs_ilock(dp, XFS_ILOCK_SHARED);
-       if (!xfs_inode_hasattr(dp) ||
-           dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
-               xfs_iunlock(dp, XFS_ILOCK_SHARED);
-               return 0;
-       }
-       xfs_iunlock(dp, XFS_ILOCK_SHARED);
+       xfs_ilock(dp, lock_mode);
+       if (!XFS_IFORK_Q(dp))
+               goto out_destroy_fork;
+       xfs_iunlock(dp, lock_mode);
 
        /*
         * Start our first transaction of the day.
@@ -407,13 +415,18 @@ xfs_attr_inactive(xfs_inode_t *dp)
         * the inode in every transaction to let it float upward through
         * the log.
         */
+       lock_mode = 0;
        trans = xfs_trans_alloc(mp, XFS_TRANS_ATTRINVAL);
        error = xfs_trans_reserve(trans, &M_RES(mp)->tr_attrinval, 0, 0);
-       if (error) {
-               xfs_trans_cancel(trans, 0);
-               return error;
-       }
-       xfs_ilock(dp, XFS_ILOCK_EXCL);
+       if (error)
+               goto out_cancel;
+
+       lock_mode = XFS_ILOCK_EXCL;
+       cancel_flags = XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT;
+       xfs_ilock(dp, lock_mode);
+
+       if (!XFS_IFORK_Q(dp))
+               goto out_cancel;
 
        /*
         * No need to make quota reservations here. We expect to release some
@@ -421,29 +434,31 @@ xfs_attr_inactive(xfs_inode_t *dp)
         */
        xfs_trans_ijoin(trans, dp, 0);
 
-       /*
-        * Decide on what work routines to call based on the inode size.
-        */
-       if (!xfs_inode_hasattr(dp) ||
-           dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
-               error = 0;
-               goto out;
+       /* invalidate and truncate the attribute fork extents */
+       if (dp->i_d.di_aformat != XFS_DINODE_FMT_LOCAL) {
+               error = xfs_attr3_root_inactive(&trans, dp);
+               if (error)
+                       goto out_cancel;
+
+               error = xfs_itruncate_extents(&trans, dp, XFS_ATTR_FORK, 0);
+               if (error)
+                       goto out_cancel;
        }
-       error = xfs_attr3_root_inactive(&trans, dp);
-       if (error)
-               goto out;
 
-       error = xfs_itruncate_extents(&trans, dp, XFS_ATTR_FORK, 0);
-       if (error)
-               goto out;
+       /* Reset the attribute fork - this also destroys the in-core fork */
+       xfs_attr_fork_remove(dp, trans);
 
        error = xfs_trans_commit(trans, XFS_TRANS_RELEASE_LOG_RES);
-       xfs_iunlock(dp, XFS_ILOCK_EXCL);
-
+       xfs_iunlock(dp, lock_mode);
        return error;
 
-out:
-       xfs_trans_cancel(trans, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
-       xfs_iunlock(dp, XFS_ILOCK_EXCL);
+out_cancel:
+       xfs_trans_cancel(trans, cancel_flags);
+out_destroy_fork:
+       /* kill the in-core attr fork before we drop the inode lock */
+       if (dp->i_afp)
+               xfs_idestroy_fork(dp, XFS_ATTR_FORK);
+       if (lock_mode)
+               xfs_iunlock(dp, lock_mode);
        return error;
 }

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 6163767aa8562f6d611a1442ed4f299aa85bceea..b1edda7890f41b60ea57e82bb5f1c22a0ddabbb6 100644 (file)
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1889,21 +1889,17 @@ xfs_inactive(
        /*
         * If there are attributes associated with the file then blow them away
         * now.  The code calls a routine that recursively deconstructs the
-        * attribute fork.  We need to just commit the current transaction
-        * because we can't use it for xfs_attr_inactive().
+        * attribute fork. If also blows away the in-core attribute fork.
         */
-       if (ip->i_d.di_anextents > 0) {
-               ASSERT(ip->i_d.di_forkoff != 0);
-
+       if (XFS_IFORK_Q(ip)) {
                error = xfs_attr_inactive(ip);
                if (error)
                        return;
        }
 
-       if (ip->i_afp)
-               xfs_idestroy_fork(ip, XFS_ATTR_FORK);
-
+       ASSERT(!ip->i_afp);
        ASSERT(ip->i_d.di_anextents == 0);
+       ASSERT(ip->i_d.di_forkoff == 0);
 
        /*
         * Free the inode.