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authorBrian Foster <bfoster@redhat.com>2014-09-23 07:39:04 +0200
committerDave Chinner <david@fromorbit.com>2014-09-23 07:39:04 +0200
commita979bdfea10a61dce0055b4d416d640f4f5f495e (patch)
treeef48ae3ce031f6133fa2c9c56d01f6d31fe4d953 /fs/xfs/libxfs
parentxfs: refactor shift-by-merge into xfs_bmse_merge() helper (diff)
downloadlinux-a979bdfea10a61dce0055b4d416d640f4f5f495e.tar.xz
linux-a979bdfea10a61dce0055b4d416d640f4f5f495e.zip
xfs: refactor single extent shift into xfs_bmse_shift_one() helper
xfs_bmap_shift_extents() has a variety of conditions and error checks that make the logic difficult to follow and indent heavy. Refactor the loop body of this function into a new xfs_bmse_shift_one() helper. This simplifies the error checks, eliminates index decrement on merge hack by pushing the index increment down into the helper, and makes the code more readable by reducing multiple levels of indentation. This is a code refactor only. The behavior of extent shift and collapse range is not modified. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs/libxfs')
-rw-r--r--fs/xfs/libxfs/xfs_bmap.c164
1 files changed, 91 insertions, 73 deletions
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 532c4aab20f2..69bf8d868b64 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -5518,6 +5518,88 @@ out_error:
}
/*
+ * Shift a single extent.
+ */
+STATIC int
+xfs_bmse_shift_one(
+ struct xfs_inode *ip,
+ int whichfork,
+ xfs_fileoff_t offset_shift_fsb,
+ int *current_ext,
+ struct xfs_bmbt_rec_host *gotp,
+ struct xfs_btree_cur *cur,
+ int *logflags)
+{
+ struct xfs_ifork *ifp;
+ xfs_fileoff_t startoff;
+ struct xfs_bmbt_rec_host *leftp;
+ struct xfs_bmbt_irec got;
+ struct xfs_bmbt_irec left;
+ int error;
+ int i;
+
+ ifp = XFS_IFORK_PTR(ip, whichfork);
+
+ xfs_bmbt_get_all(gotp, &got);
+ startoff = got.br_startoff - offset_shift_fsb;
+
+ /*
+ * If this is the first extent in the file, make sure there's enough
+ * room at the start of the file and jump right to the shift as there's
+ * no left extent to merge.
+ */
+ if (*current_ext == 0) {
+ if (got.br_startoff < offset_shift_fsb)
+ return -EINVAL;
+ goto shift_extent;
+ }
+
+ /* grab the left extent and check for a large enough hole */
+ leftp = xfs_iext_get_ext(ifp, *current_ext - 1);
+ xfs_bmbt_get_all(leftp, &left);
+
+ if (startoff < left.br_startoff + left.br_blockcount)
+ return -EINVAL;
+
+ /* check whether to merge the extent or shift it down */
+ if (!xfs_bmse_can_merge(&left, &got, offset_shift_fsb))
+ goto shift_extent;
+
+ return xfs_bmse_merge(ip, whichfork, offset_shift_fsb, *current_ext,
+ gotp, leftp, cur, logflags);
+
+shift_extent:
+ /*
+ * Increment the extent index for the next iteration, update the start
+ * offset of the in-core extent and update the btree if applicable.
+ */
+ (*current_ext)++;
+ xfs_bmbt_set_startoff(gotp, startoff);
+ *logflags |= XFS_ILOG_CORE;
+ if (!cur) {
+ *logflags |= XFS_ILOG_DEXT;
+ return 0;
+ }
+
+ error = xfs_bmbt_lookup_eq(cur, got.br_startoff, got.br_startblock,
+ got.br_blockcount, &i);
+ if (error)
+ return error;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, out_error);
+
+ got.br_startoff = startoff;
+ error = xfs_bmbt_update(cur, got.br_startoff, got.br_startblock,
+ got.br_blockcount, got.br_state);
+ if (error)
+ return error;
+
+ return 0;
+
+out_error:
+ return error;
+}
+
+/*
* Shift extent records to the left to cover a hole.
*
* The maximum number of extents to be shifted in a single operation is
@@ -5541,16 +5623,12 @@ xfs_bmap_shift_extents(
{
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;
struct xfs_ifork *ifp;
xfs_extnum_t nexts = 0;
xfs_extnum_t current_ext;
- xfs_fileoff_t startoff;
int error = 0;
- int i;
int whichfork = XFS_DATA_FORK;
int logflags = 0;
int total_extents;
@@ -5599,16 +5677,6 @@ xfs_bmap_shift_extents(
*done = 1;
goto del_cursor;
}
- xfs_bmbt_get_all(gotp, &got);
-
- /*
- * 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;
- }
/*
* There may be delalloc extents in the data fork before the range we
@@ -5617,75 +5685,25 @@ xfs_bmap_shift_extents(
*/
total_extents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);
while (nexts++ < num_exts && current_ext < total_extents) {
- startoff = got.br_startoff - offset_shift_fsb;
-
- /* grab the left extent and check for a potential merge */
- if (current_ext > 0) {
- 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;
- 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;
- }
- }
-
- /*
- * 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,
- got.br_blockcount,
- &i);
- if (error)
- goto del_cursor;
- XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
-
- got.br_startoff = startoff;
- error = xfs_bmbt_update(cur, got.br_startoff,
- got.br_startblock,
- got.br_blockcount,
- got.br_state);
- if (error)
- goto del_cursor;
- } else {
- logflags |= XFS_ILOG_DEXT;
- }
+ error = xfs_bmse_shift_one(ip, whichfork, offset_shift_fsb,
+ &current_ext, gotp, cur, &logflags);
+ if (error)
+ goto del_cursor;
-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)
+ 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)
+ if (current_ext == total_extents) {
*done = 1;
- else if (next_fsb)
+ } else if (next_fsb) {
+ xfs_bmbt_get_all(gotp, &got);
*next_fsb = got.br_startoff;
+ }
del_cursor:
if (cur)