xfs: remote attribute overwrite causes transaction overrun

Commit e461fcb ("xfs: remote attribute lookups require the value
length") passes the remote attribute length in the xfs_da_args
structure on lookup so that CRC calculations and validity checking
can be performed correctly by related code. This, unfortunately has
the side effect of changing the args->valuelen parameter in cases
where it shouldn't.

That is, when we replace a remote attribute, the incoming
replacement stores the value and length in args->value and
args->valuelen, but then the lookup which finds the existing remote
attribute overwrites args->valuelen with the length of the remote
attribute being replaced. Hence when we go to create the new
attribute, we create it of the size of the existing remote
attribute, not the size it is supposed to be. When the new attribute
is much smaller than the old attribute, this results in a
transaction overrun and an ASSERT() failure on a debug kernel:

XFS: Assertion failed: tp->t_blk_res_used <= tp->t_blk_res, file: fs/xfs/xfs_trans.c, line: 331

Fix this by keeping the remote attribute value length separate to
the attribute value length in the xfs_da_args structure. The enables
us to pass the length of the remote attribute to be removed without
overwriting the new attribute's length.

Also, ensure that when we save remote block contexts for a later
rename we zero the original state variables so that we don't confuse
the state of the attribute to be removes with the state of the new
attribute that we just added. [Spotted by Brain Foster.]

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_attr.c b/fs/xfs/xfs_attr.c
index 01b6a0102fbdd4d153612740d95c4f00fda691f7..abda1124a70f66fbd1a79b28f8eaf5bf1916da1e 100644 (file)
--- a/fs/xfs/xfs_attr.c
+++ b/fs/xfs/xfs_attr.c
@@ -213,7 +213,7 @@ xfs_attr_calc_size(
                 * Out of line attribute, cannot double split, but
                 * make room for the attribute value itself.
                 */
-               uint    dblocks = XFS_B_TO_FSB(mp, valuelen);
+               uint    dblocks = xfs_attr3_rmt_blocks(mp, valuelen);
                nblks += dblocks;
                nblks += XFS_NEXTENTADD_SPACE_RES(mp, dblocks, XFS_ATTR_FORK);
        }
@@ -698,11 +698,22 @@ xfs_attr_leaf_addname(xfs_da_args_t *args)
 
                trace_xfs_attr_leaf_replace(args);
 
+               /* save the attribute state for later removal*/
                args->op_flags |= XFS_DA_OP_RENAME;     /* an atomic rename */
                args->blkno2 = args->blkno;             /* set 2nd entry info*/
                args->index2 = args->index;
                args->rmtblkno2 = args->rmtblkno;
                args->rmtblkcnt2 = args->rmtblkcnt;
+               args->rmtvaluelen2 = args->rmtvaluelen;
+
+               /*
+                * clear the remote attr state now that it is saved so that the
+                * values reflect the state of the attribute we are about to
+                * add, not the attribute we just found and will remove later.
+                */
+               args->rmtblkno = 0;
+               args->rmtblkcnt = 0;
+               args->rmtvaluelen = 0;
        }
 
        /*
@@ -794,6 +805,7 @@ xfs_attr_leaf_addname(xfs_da_args_t *args)
                args->blkno = args->blkno2;
                args->rmtblkno = args->rmtblkno2;
                args->rmtblkcnt = args->rmtblkcnt2;
+               args->rmtvaluelen = args->rmtvaluelen2;
                if (args->rmtblkno) {
                        error = xfs_attr_rmtval_remove(args);
                        if (error)
@@ -999,13 +1011,22 @@ restart:
 
                trace_xfs_attr_node_replace(args);
 
+               /* save the attribute state for later removal*/
                args->op_flags |= XFS_DA_OP_RENAME;     /* atomic rename op */
                args->blkno2 = args->blkno;             /* set 2nd entry info*/
                args->index2 = args->index;
                args->rmtblkno2 = args->rmtblkno;
                args->rmtblkcnt2 = args->rmtblkcnt;
+               args->rmtvaluelen2 = args->rmtvaluelen;
+
+               /*
+                * clear the remote attr state now that it is saved so that the
+                * values reflect the state of the attribute we are about to
+                * add, not the attribute we just found and will remove later.
+                */
                args->rmtblkno = 0;
                args->rmtblkcnt = 0;
+               args->rmtvaluelen = 0;
        }
 
        retval = xfs_attr3_leaf_add(blk->bp, state->args);
@@ -1133,6 +1154,7 @@ restart:
                args->blkno = args->blkno2;
                args->rmtblkno = args->rmtblkno2;
                args->rmtblkcnt = args->rmtblkcnt2;
+               args->rmtvaluelen = args->rmtvaluelen2;
                if (args->rmtblkno) {
                        error = xfs_attr_rmtval_remove(args);
                        if (error)

diff --git a/fs/xfs/xfs_attr_leaf.c b/fs/xfs/xfs_attr_leaf.c
index fe9587fab17a6822d9bec1b5862a6a133adf9dc7..511c283459b19441d782114c4f832207860deab1 100644 (file)
--- a/fs/xfs/xfs_attr_leaf.c
+++ b/fs/xfs/xfs_attr_leaf.c
@@ -1229,6 +1229,7 @@ xfs_attr3_leaf_add_work(
                name_rmt->valueblk = 0;
                args->rmtblkno = 1;
                args->rmtblkcnt = xfs_attr3_rmt_blocks(mp, args->valuelen);
+               args->rmtvaluelen = args->valuelen;
        }
        xfs_trans_log_buf(args->trans, bp,
             XFS_DA_LOGRANGE(leaf, xfs_attr3_leaf_name(leaf, args->index),
@@ -2167,11 +2168,11 @@ xfs_attr3_leaf_lookup_int(
                        if (!xfs_attr_namesp_match(args->flags, entry->flags))
                                continue;
                        args->index = probe;
-                       args->valuelen = be32_to_cpu(name_rmt->valuelen);
+                       args->rmtvaluelen = be32_to_cpu(name_rmt->valuelen);
                        args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
                        args->rmtblkcnt = xfs_attr3_rmt_blocks(
                                                        args->dp->i_mount,
-                                                       args->valuelen);
+                                                       args->rmtvaluelen);
                        return XFS_ERROR(EEXIST);
                }
        }
@@ -2220,19 +2221,19 @@ xfs_attr3_leaf_getvalue(
                name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
                ASSERT(name_rmt->namelen == args->namelen);
                ASSERT(memcmp(args->name, name_rmt->name, args->namelen) == 0);
-               valuelen = be32_to_cpu(name_rmt->valuelen);
+               args->rmtvaluelen = be32_to_cpu(name_rmt->valuelen);
                args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
                args->rmtblkcnt = xfs_attr3_rmt_blocks(args->dp->i_mount,
-                                                      valuelen);
+                                                      args->rmtvaluelen);
                if (args->flags & ATTR_KERNOVAL) {
-                       args->valuelen = valuelen;
+                       args->valuelen = args->rmtvaluelen;
                        return 0;
                }
-               if (args->valuelen < valuelen) {
-                       args->valuelen = valuelen;
+               if (args->valuelen < args->rmtvaluelen) {
+                       args->valuelen = args->rmtvaluelen;
                        return XFS_ERROR(ERANGE);
                }
-               args->valuelen = valuelen;
+               args->valuelen = args->rmtvaluelen;
        }
        return 0;
 }
@@ -2519,7 +2520,7 @@ xfs_attr3_leaf_clearflag(
                ASSERT((entry->flags & XFS_ATTR_LOCAL) == 0);
                name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
                name_rmt->valueblk = cpu_to_be32(args->rmtblkno);
-               name_rmt->valuelen = cpu_to_be32(args->valuelen);
+               name_rmt->valuelen = cpu_to_be32(args->rmtvaluelen);
                xfs_trans_log_buf(args->trans, bp,
                         XFS_DA_LOGRANGE(leaf, name_rmt, sizeof(*name_rmt)));
        }
@@ -2677,7 +2678,7 @@ xfs_attr3_leaf_flipflags(
                ASSERT((entry1->flags & XFS_ATTR_LOCAL) == 0);
                name_rmt = xfs_attr3_leaf_name_remote(leaf1, args->index);
                name_rmt->valueblk = cpu_to_be32(args->rmtblkno);
-               name_rmt->valuelen = cpu_to_be32(args->valuelen);
+               name_rmt->valuelen = cpu_to_be32(args->rmtvaluelen);
                xfs_trans_log_buf(args->trans, bp1,
                         XFS_DA_LOGRANGE(leaf1, name_rmt, sizeof(*name_rmt)));
        }

diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
index 01db96f60cf05abf1f42e20252cdff4de0ebea0d..833fe5d98d806783ca6bb6cf2f4ecb83424bfdca 100644 (file)
--- a/fs/xfs/xfs_attr_list.c
+++ b/fs/xfs/xfs_attr_list.c
@@ -447,6 +447,7 @@ xfs_attr3_leaf_list_int(
                                args.dp = context->dp;
                                args.whichfork = XFS_ATTR_FORK;
                                args.valuelen = valuelen;
+                               args.rmtvaluelen = valuelen;
                                args.value = kmem_alloc(valuelen, KM_SLEEP | KM_NOFS);
                                args.rmtblkno = be32_to_cpu(name_rmt->valueblk);
                                args.rmtblkcnt = xfs_attr3_rmt_blocks(

diff --git a/fs/xfs/xfs_attr_remote.c b/fs/xfs/xfs_attr_remote.c
index 6e37823e2932aeb45d112b55010ab627adb5bde2..d2e6e948cec7be3013b853033b6e1a64b365a682 100644 (file)
--- a/fs/xfs/xfs_attr_remote.c
+++ b/fs/xfs/xfs_attr_remote.c
@@ -337,7 +337,7 @@ xfs_attr_rmtval_get(
        struct xfs_buf          *bp;
        xfs_dablk_t             lblkno = args->rmtblkno;
        __uint8_t               *dst = args->value;
-       int                     valuelen = args->valuelen;
+       int                     valuelen;
        int                     nmap;
        int                     error;
        int                     blkcnt = args->rmtblkcnt;
@@ -347,7 +347,9 @@ xfs_attr_rmtval_get(
        trace_xfs_attr_rmtval_get(args);
 
        ASSERT(!(args->flags & ATTR_KERNOVAL));
+       ASSERT(args->rmtvaluelen == args->valuelen);
 
+       valuelen = args->rmtvaluelen;
        while (valuelen > 0) {
                nmap = ATTR_RMTVALUE_MAPSIZE;
                error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
@@ -415,7 +417,7 @@ xfs_attr_rmtval_set(
         * attributes have headers, we can't just do a straight byte to FSB
         * conversion and have to take the header space into account.
         */
-       blkcnt = xfs_attr3_rmt_blocks(mp, args->valuelen);
+       blkcnt = xfs_attr3_rmt_blocks(mp, args->rmtvaluelen);
        error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
                                                   XFS_ATTR_FORK);
        if (error)
@@ -480,7 +482,7 @@ xfs_attr_rmtval_set(
         */
        lblkno = args->rmtblkno;
        blkcnt = args->rmtblkcnt;
-       valuelen = args->valuelen;
+       valuelen = args->rmtvaluelen;
        while (valuelen > 0) {
                struct xfs_buf  *bp;
                xfs_daddr_t     dblkno;

diff --git a/fs/xfs/xfs_da_btree.h b/fs/xfs/xfs_da_btree.h
index 6e95ea79f5d73aa2447fc49eb0e4c7e9bb73a25d..201c6091d26abfa2e38dd17fd960e3efcb69bcd7 100644 (file)
--- a/fs/xfs/xfs_da_btree.h
+++ b/fs/xfs/xfs_da_btree.h
@@ -60,10 +60,12 @@ typedef struct xfs_da_args {
        int             index;          /* index of attr of interest in blk */
        xfs_dablk_t     rmtblkno;       /* remote attr value starting blkno */
        int             rmtblkcnt;      /* remote attr value block count */
+       int             rmtvaluelen;    /* remote attr value length in bytes */
        xfs_dablk_t     blkno2;         /* blkno of 2nd attr leaf of interest */
        int             index2;         /* index of 2nd attr in blk */
        xfs_dablk_t     rmtblkno2;      /* remote attr value starting blkno */
        int             rmtblkcnt2;     /* remote attr value block count */
+       int             rmtvaluelen2;   /* remote attr value length in bytes */
        int             op_flags;       /* operation flags */
        enum xfs_dacmp  cmpresult;      /* name compare result for lookups */
 } xfs_da_args_t;