return error;
}
+/*
+ * Determine whether an extent shift can be accomplished by a merge with the
+ * extent that precedes the target hole of the shift.
+ */
+STATIC bool
+xfs_bmse_can_merge(
+ struct xfs_bmbt_irec *left, /* preceding extent */
+ struct xfs_bmbt_irec *got, /* current extent to shift */
+ xfs_fileoff_t shift) /* shift fsb */
+{
+ xfs_fileoff_t startoff;
+
+ startoff = got->br_startoff - shift;
+
+ /*
+ * The extent, once shifted, must be adjacent in-file and on-disk with
+ * the preceding extent.
+ */
+ if ((left->br_startoff + left->br_blockcount != startoff) ||
+ (left->br_startblock + left->br_blockcount != got->br_startblock) ||
+ (left->br_state != got->br_state) ||
+ (left->br_blockcount + got->br_blockcount > MAXEXTLEN))
+ return false;
+
+ return true;
+}
+
+/*
+ * A bmap extent shift adjusts the file offset of an extent to fill a preceding
+ * hole in the file. If an extent shift would result in the extent being fully
+ * adjacent to the extent that currently precedes the hole, we can merge with
+ * the preceding extent rather than do the shift.
+ *
+ * This function assumes the caller has verified a shift-by-merge is possible
+ * with the provided extents via xfs_bmse_can_merge().
+ */
+STATIC int
+xfs_bmse_merge(
+ struct xfs_inode *ip,
+ int whichfork,
+ xfs_fileoff_t shift, /* shift fsb */
+ int current_ext, /* idx of gotp */
+ struct xfs_bmbt_rec_host *gotp, /* extent to shift */
+ struct xfs_bmbt_rec_host *leftp, /* preceding extent */
+ struct xfs_btree_cur *cur,
+ int *logflags) /* output */
+{
+ struct xfs_ifork *ifp;
+ struct xfs_bmbt_irec got;
+ struct xfs_bmbt_irec left;
+ xfs_filblks_t blockcount;
+ int error, i;
+
+ ifp = XFS_IFORK_PTR(ip, whichfork);
+ xfs_bmbt_get_all(gotp, &got);
+ xfs_bmbt_get_all(leftp, &left);
+ blockcount = left.br_blockcount + got.br_blockcount;
+
+ ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+ ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+ ASSERT(xfs_bmse_can_merge(&left, &got, shift));
+
+ /*
+ * Merge the in-core extents. Note that the host record pointers and
+ * current_ext index are invalid once the extent has been removed via
+ * xfs_iext_remove().
+ */
+ xfs_bmbt_set_blockcount(leftp, blockcount);
+ xfs_iext_remove(ip, current_ext, 1, 0);
+
+ /*
+ * Update the on-disk extent count, the btree if necessary and log the
+ * inode.
+ */
+ XFS_IFORK_NEXT_SET(ip, whichfork,
+ XFS_IFORK_NEXTENTS(ip, whichfork) - 1);
+ *logflags |= XFS_ILOG_CORE;
+ if (!cur) {
+ *logflags |= XFS_ILOG_DEXT;
+ return 0;
+ }
+
+ /* lookup and remove the extent to merge */
+ error = xfs_bmbt_lookup_eq(cur, got.br_startoff, got.br_startblock,
+ got.br_blockcount, &i);
+ if (error)
+ goto out_error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, out_error);
+
+ error = xfs_btree_delete(cur, &i);
+ if (error)
+ goto out_error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, out_error);
+
+ /* lookup and update size of the previous extent */
+ error = xfs_bmbt_lookup_eq(cur, left.br_startoff, left.br_startblock,
+ left.br_blockcount, &i);
+ if (error)
+ goto out_error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, out_error);
+
+ left.br_blockcount = blockcount;
+
+ error = xfs_bmbt_update(cur, left.br_startoff, left.br_startblock,
+ left.br_blockcount, left.br_state);
+ if (error)
+ goto out_error;
+
+ return 0;
+
+out_error:
+ return error;
+}
+
/*
* Shift extent records to the left to cover a hole.
*
{
struct xfs_btree_cur *cur = NULL;
struct xfs_bmbt_rec_host *gotp;
+ struct xfs_bmbt_rec_host *leftp;
struct xfs_bmbt_irec got;
struct xfs_bmbt_irec left;
struct xfs_mount *mp = ip->i_mount;
int i;
int whichfork = XFS_DATA_FORK;
int logflags = 0;
- xfs_filblks_t blockcount = 0;
int total_extents;
if (unlikely(XFS_TEST_ERROR(
return error;
}
+ if (ifp->if_flags & XFS_IFBROOT) {
+ cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
+ cur->bc_private.b.firstblock = *firstblock;
+ cur->bc_private.b.flist = flist;
+ cur->bc_private.b.flags = 0;
+ }
+
/*
* Look up the extent index for the fsb where we start shifting. We can
* henceforth iterate with current_ext as extent list changes are locked
gotp = xfs_iext_bno_to_ext(ifp, start_fsb, ¤t_ext);
if (!gotp) {
*done = 1;
- return 0;
+ goto del_cursor;
}
+ xfs_bmbt_get_all(gotp, &got);
- if (ifp->if_flags & XFS_IFBROOT) {
- cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
- cur->bc_private.b.firstblock = *firstblock;
- cur->bc_private.b.flist = flist;
- cur->bc_private.b.flags = 0;
+ /*
+ * If the first extent is shifted, offset_shift_fsb cannot be larger
+ * than the starting offset of the first extent.
+ */
+ if (current_ext == 0 && got.br_startoff < offset_shift_fsb) {
+ error = -EINVAL;
+ goto del_cursor;
}
/*
*/
total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
while (nexts++ < num_exts && current_ext < total_extents) {
-
- gotp = xfs_iext_get_ext(ifp, current_ext);
- xfs_bmbt_get_all(gotp, &got);
startoff = got.br_startoff - offset_shift_fsb;
- /*
- * Before shifting extent into hole, make sure that the hole is
- * large enough to accommodate the shift.
- */
+ /* grab the left extent and check for a potential merge */
if (current_ext > 0) {
- xfs_bmbt_get_all(xfs_iext_get_ext(ifp, current_ext - 1),
- &left);
- if (startoff < left.br_startoff + left.br_blockcount)
+ leftp = xfs_iext_get_ext(ifp, current_ext - 1);
+ xfs_bmbt_get_all(leftp, &left);
+
+ /* make sure hole is large enough for shift */
+ if (startoff < left.br_startoff + left.br_blockcount) {
error = -EINVAL;
- } else if (offset_shift_fsb > got.br_startoff) {
- /*
- * When first extent is shifted, offset_shift_fsb should
- * be less than the stating offset of the first extent.
- */
- error = -EINVAL;
+ goto del_cursor;
+ }
+
+ if (xfs_bmse_can_merge(&left, &got, offset_shift_fsb)) {
+ error = xfs_bmse_merge(ip, whichfork,
+ offset_shift_fsb, current_ext, gotp,
+ leftp, cur, &logflags);
+ if (error)
+ goto del_cursor;
+
+ /*
+ * The extent was merged so adjust the extent
+ * index and move onto the next.
+ */
+ current_ext--;
+ goto next;
+ }
}
- if (error)
- goto del_cursor;
+ /*
+ * We didn't merge the extent so do the shift. Update the start
+ * offset in the in-core extent and btree, if necessary.
+ */
+ xfs_bmbt_set_startoff(gotp, startoff);
+ logflags |= XFS_ILOG_CORE;
if (cur) {
error = xfs_bmbt_lookup_eq(cur, got.br_startoff,
got.br_startblock,
if (error)
goto del_cursor;
XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
- }
-
- /* Check if we can merge 2 adjacent extents */
- if (current_ext &&
- left.br_startoff + left.br_blockcount == startoff &&
- left.br_startblock + left.br_blockcount ==
- got.br_startblock &&
- left.br_state == got.br_state &&
- left.br_blockcount + got.br_blockcount <= MAXEXTLEN) {
- blockcount = left.br_blockcount +
- got.br_blockcount;
- xfs_iext_remove(ip, current_ext, 1, 0);
- logflags |= XFS_ILOG_CORE;
- if (cur) {
- error = xfs_btree_delete(cur, &i);
- if (error)
- goto del_cursor;
- XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
- } else {
- logflags |= XFS_ILOG_DEXT;
- }
- XFS_IFORK_NEXT_SET(ip, whichfork,
- XFS_IFORK_NEXTENTS(ip, whichfork) - 1);
- gotp = xfs_iext_get_ext(ifp, --current_ext);
- xfs_bmbt_get_all(gotp, &got);
-
- /* Make cursor point to the extent we will update */
- if (cur) {
- error = xfs_bmbt_lookup_eq(cur, got.br_startoff,
- got.br_startblock,
- got.br_blockcount,
- &i);
- if (error)
- goto del_cursor;
- XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
- }
- xfs_bmbt_set_blockcount(gotp, blockcount);
- got.br_blockcount = blockcount;
- } else {
- /* We have to update the startoff */
- xfs_bmbt_set_startoff(gotp, startoff);
got.br_startoff = startoff;
- }
-
- logflags |= XFS_ILOG_CORE;
- if (cur) {
error = xfs_bmbt_update(cur, got.br_startoff,
got.br_startblock,
got.br_blockcount,
logflags |= XFS_ILOG_DEXT;
}
- current_ext++;
+next:
+ /* update total extent count and grab the next record */
total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
+ if (++current_ext >= total_extents)
+ break;
+ gotp = xfs_iext_get_ext(ifp, current_ext);
+ xfs_bmbt_get_all(gotp, &got);
}
/* Check if we are done */
if (current_ext == total_extents)
*done = 1;
- else if (next_fsb) {
- gotp = xfs_iext_get_ext(ifp, current_ext);
- xfs_bmbt_get_all(gotp, &got);
+ else if (next_fsb)
*next_fsb = got.br_startoff;
- }
del_cursor:
if (cur)
projects / firefly-linux-kernel-4.4.55.git / commitdiff