To further improve the readability of xfs_bmapi(), factor the extent
allocation out into a separate function. This removes a large block
of logic from the xfs_bmapi() code loop and makes it easier to see
the operational logic flow for xfs_bmapi().
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Index: xfs/fs/xfs/xfs_bmap.c
===================================================================
--- xfs.orig/fs/xfs/xfs_bmap.c 2011-08-23 21:13:31.625760927 +0200
+++ xfs/fs/xfs/xfs_bmap.c 2011-08-23 21:13:33.855748845 +0200
@@ -4602,6 +4602,147 @@ xfs_bmapi_delay(
}
+STATIC int
+xfs_bmapi_allocate(
+ struct xfs_bmalloca *bma,
+ xfs_extnum_t *lastx,
+ struct xfs_btree_cur **cur,
+ xfs_fsblock_t *firstblock,
+ struct xfs_bmap_free *flist,
+ int flags,
+ int *nallocs,
+ int *logflags)
+{
+ struct xfs_mount *mp = bma->ip->i_mount;
+ int whichfork = (flags & XFS_BMAPI_ATTRFORK) ?
+ XFS_ATTR_FORK : XFS_DATA_FORK;
+ struct xfs_ifork *ifp = XFS_IFORK_PTR(bma->ip, whichfork);
+ xfs_fsblock_t abno;
+ xfs_extlen_t alen;
+ xfs_fileoff_t aoff;
+ int error;
+ int rt;
+
+ rt = (whichfork == XFS_DATA_FORK) && XFS_IS_REALTIME_INODE(bma->ip);
+
+ /*
+ * For the wasdelay case, we could also just allocate the stuff asked
+ * for in this bmap call but that wouldn't be as good.
+ */
+ if (bma->wasdel) {
+ alen = (xfs_extlen_t)bma->gotp->br_blockcount;
+ aoff = bma->gotp->br_startoff;
+ if (*lastx != NULLEXTNUM && *lastx) {
+ xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx - 1),
+ bma->prevp);
+ }
+ } else {
+ alen = (xfs_extlen_t)XFS_FILBLKS_MIN(bma->alen, MAXEXTLEN);
+ if (!bma->eof)
+ alen = (xfs_extlen_t)XFS_FILBLKS_MIN(alen,
+ bma->gotp->br_startoff - bma->off);
+ aoff = bma->off;
+ }
+
+ /*
+ * Indicate if this is the first user data in the file, or just any
+ * user data.
+ */
+ if (!(flags & XFS_BMAPI_METADATA)) {
+ bma->userdata = (aoff == 0) ?
+ XFS_ALLOC_INITIAL_USER_DATA : XFS_ALLOC_USERDATA;
+ }
+
+ /*
+ * Fill in changeable bma fields.
+ */
+ bma->alen = alen;
+ bma->off = aoff;
+ bma->firstblock = *firstblock;
+ bma->minlen = (flags & XFS_BMAPI_CONTIG) ? alen : 1;
+ bma->low = flist->xbf_low;
+ bma->aeof = 0;
+
+ /*
+ * Only want to do the alignment at the eof if it is userdata and
+ * allocation length is larger than a stripe unit.
+ */
+ if (mp->m_dalign && alen >= mp->m_dalign &&
+ !(flags & XFS_BMAPI_METADATA) && whichfork == XFS_DATA_FORK) {
+ error = xfs_bmap_isaeof(bma->ip, aoff, whichfork, &bma->aeof);
+ if (error)
+ return error;
+ }
+
+ error = xfs_bmap_alloc(bma);
+ if (error)
+ return error;
+
+ /*
+ * Copy out result fields.
+ */
+ abno = bma->rval;
+ flist->xbf_low = bma->low;
+ alen = bma->alen;
+ aoff = bma->off;
+ ASSERT(*firstblock == NULLFSBLOCK ||
+ XFS_FSB_TO_AGNO(mp, *firstblock) ==
+ XFS_FSB_TO_AGNO(mp, bma->firstblock) ||
+ (flist->xbf_low &&
+ XFS_FSB_TO_AGNO(mp, *firstblock) <
+ XFS_FSB_TO_AGNO(mp, bma->firstblock)));
+ *firstblock = bma->firstblock;
+ if (*cur)
+ (*cur)->bc_private.b.firstblock = *firstblock;
+ if (abno == NULLFSBLOCK)
+ return 0;
+ if ((ifp->if_flags & XFS_IFBROOT) && !*cur) {
+ (*cur) = xfs_bmbt_init_cursor(mp, bma->tp, bma->ip, whichfork);
+ (*cur)->bc_private.b.firstblock = *firstblock;
+ (*cur)->bc_private.b.flist = flist;
+ }
+ /*
+ * Bump the number of extents we've allocated
+ * in this call.
+ */
+ (*nallocs)++;
+
+ if (*cur)
+ (*cur)->bc_private.b.flags =
+ bma->wasdel ? XFS_BTCUR_BPRV_WASDEL : 0;
+
+ bma->gotp->br_startoff = aoff;
+ bma->gotp->br_startblock = abno;
+ bma->gotp->br_blockcount = alen;
+ bma->gotp->br_state = XFS_EXT_NORM;
+
+ /*
+ * A wasdelay extent has been initialized, so shouldn't be flagged
+ * as unwritten.
+ */
+ if (!bma->wasdel && (flags & XFS_BMAPI_PREALLOC) &&
+ xfs_sb_version_hasextflgbit(&mp->m_sb))
+ bma->gotp->br_state = XFS_EXT_UNWRITTEN;
+
+ error = xfs_bmap_add_extent(bma->tp, bma->ip, lastx, cur, bma->gotp,
+ firstblock, flist, logflags, whichfork);
+ if (error)
+ return error;
+
+ /*
+ * Update our extent pointer, given that xfs_bmap_add_extent might
+ * have merged it into one of the neighbouring ones.
+ */
+ xfs_bmbt_get_all(xfs_iext_get_ext(ifp, *lastx), bma->gotp);
+
+ ASSERT(bma->gotp->br_startoff <= aoff);
+ ASSERT(bma->gotp->br_startoff + bma->gotp->br_blockcount >=
+ aoff + alen);
+ ASSERT(bma->gotp->br_state == XFS_EXT_NORM ||
+ bma->gotp->br_state == XFS_EXT_UNWRITTEN);
+ return 0;
+}
+
/*
* Map file blocks to filesystem blocks.
* File range is given by the bno/len pair.
@@ -4629,9 +4770,6 @@ xfs_bmapi(
int *nmap, /* i/o: mval size/count */
xfs_bmap_free_t *flist) /* i/o: list extents to free */
{
- xfs_fsblock_t abno; /* allocated block number */
- xfs_extlen_t alen; /* allocated extent length */
- xfs_fileoff_t aoff; /* allocated file offset */
xfs_bmalloca_t bma = { 0 }; /* args for xfs_bmap_alloc */
xfs_btree_cur_t *cur; /* bmap btree cursor */
xfs_fileoff_t end; /* end of mapped file region */
@@ -4643,7 +4781,6 @@ xfs_bmapi(
xfs_extnum_t lastx; /* last useful extent number */
int logflags; /* flags for transaction logging */
xfs_extlen_t minleft; /* min blocks left after allocation */
- xfs_extlen_t minlen; /* min allocation size */
xfs_mount_t *mp; /* xfs mount structure */
int n; /* current extent index */
int nallocs; /* number of extents alloc'd */
@@ -4734,7 +4871,13 @@ xfs_bmapi(
n = 0;
end = bno + len;
obno = bno;
- bma.ip = NULL;
+
+ bma.tp = tp;
+ bma.ip = ip;
+ bma.prevp = &prev;
+ bma.gotp = &got;
+ bma.total = total;
+ bma.userdata = 0;
while (bno < end && n < *nmap) {
/*
@@ -4750,144 +4893,31 @@ xfs_bmapi(
* that we found, if any.
*/
if (wr && (inhole || wasdelay)) {
- /*
- * For the wasdelay case, we could also just
- * allocate the stuff asked for in this bmap call
- * but that wouldn't be as good.
- */
- if (wasdelay) {
- alen = (xfs_extlen_t)got.br_blockcount;
- aoff = got.br_startoff;
- if (lastx != NULLEXTNUM && lastx) {
- ep = xfs_iext_get_ext(ifp, lastx - 1);
- xfs_bmbt_get_all(ep, &prev);
- }
- } else {
- alen = (xfs_extlen_t)
- XFS_FILBLKS_MIN(len, MAXEXTLEN);
- if (!eof)
- alen = (xfs_extlen_t)
- XFS_FILBLKS_MIN(alen,
- got.br_startoff - bno);
- aoff = bno;
- }
- minlen = (flags & XFS_BMAPI_CONTIG) ? alen : 1;
- {
- /*
- * If first time, allocate and fill in
- * once-only bma fields.
- */
- if (bma.ip == NULL) {
- bma.tp = tp;
- bma.ip = ip;
- bma.prevp = &prev;
- bma.gotp = &got;
- bma.total = total;
- bma.userdata = 0;
- }
- /* Indicate if this is the first user data
- * in the file, or just any user data.
- */
- if (!(flags & XFS_BMAPI_METADATA)) {
- bma.userdata = (aoff == 0) ?
- XFS_ALLOC_INITIAL_USER_DATA :
- XFS_ALLOC_USERDATA;
- }
- /*
- * Fill in changeable bma fields.
- */
- bma.eof = eof;
- bma.firstblock = *firstblock;
- bma.alen = alen;
- bma.off = aoff;
- bma.conv = !!(flags & XFS_BMAPI_CONVERT);
- bma.wasdel = wasdelay;
- bma.minlen = minlen;
- bma.low = flist->xbf_low;
- bma.minleft = minleft;
- /*
- * Only want to do the alignment at the
- * eof if it is userdata and allocation length
- * is larger than a stripe unit.
- */
- if (mp->m_dalign && alen >= mp->m_dalign &&
- (!(flags & XFS_BMAPI_METADATA)) &&
- (whichfork == XFS_DATA_FORK)) {
- if ((error = xfs_bmap_isaeof(ip, aoff,
- whichfork, &bma.aeof)))
- goto error0;
- } else
- bma.aeof = 0;
- /*
- * Call allocator.
- */
- if ((error = xfs_bmap_alloc(&bma)))
- goto error0;
- /*
- * Copy out result fields.
- */
- abno = bma.rval;
- if ((flist->xbf_low = bma.low))
- minleft = 0;
- alen = bma.alen;
- aoff = bma.off;
- ASSERT(*firstblock == NULLFSBLOCK ||
- XFS_FSB_TO_AGNO(mp, *firstblock) ==
- XFS_FSB_TO_AGNO(mp, bma.firstblock) ||
- (flist->xbf_low &&
- XFS_FSB_TO_AGNO(mp, *firstblock) <
- XFS_FSB_TO_AGNO(mp, bma.firstblock)));
- *firstblock = bma.firstblock;
- if (cur)
- cur->bc_private.b.firstblock =
- *firstblock;
- if (abno == NULLFSBLOCK)
- break;
- if ((ifp->if_flags & XFS_IFBROOT) && !cur) {
- cur = xfs_bmbt_init_cursor(mp, tp,
- ip, whichfork);
- cur->bc_private.b.firstblock =
- *firstblock;
- cur->bc_private.b.flist = flist;
+ bma.eof = eof;
+ bma.conv = !!(flags & XFS_BMAPI_CONVERT);
+ bma.wasdel = wasdelay;
+ bma.alen = len;
+ bma.off = bno;
+ bma.minleft = minleft;
+
+ error = xfs_bmapi_allocate(&bma, &lastx, &cur,
+ firstblock, flist, flags, &nallocs,
+ &tmp_logflags);
+ if (error == ENOSPC || error == EDQUOT) {
+ if (n == 0) {
+ *nmap = 0;
+ ASSERT(cur == NULL);
+ return error;
}
- /*
- * Bump the number of extents we've allocated
- * in this call.
- */
- nallocs++;
- }
- if (cur)
- cur->bc_private.b.flags =
- wasdelay ? XFS_BTCUR_BPRV_WASDEL : 0;
- got.br_startoff = aoff;
- got.br_startblock = abno;
- got.br_blockcount = alen;
- got.br_state = XFS_EXT_NORM; /* assume normal */
- /*
- * Determine state of extent, and the filesystem.
- * A wasdelay extent has been initialized, so
- * shouldn't be flagged as unwritten.
- */
- if (wr && xfs_sb_version_hasextflgbit(&mp->m_sb)) {
- if (!wasdelay && (flags & XFS_BMAPI_PREALLOC))
- got.br_state = XFS_EXT_UNWRITTEN;
}
- error = xfs_bmap_add_extent(tp, ip, &lastx, &cur, &got,
- firstblock, flist, &tmp_logflags,
- whichfork);
+
logflags |= tmp_logflags;
if (error)
goto error0;
- ep = xfs_iext_get_ext(ifp, lastx);
- xfs_bmbt_get_all(ep, &got);
- ASSERT(got.br_startoff <= aoff);
- ASSERT(got.br_startoff + got.br_blockcount >=
- aoff + alen);
- ASSERT(got.br_state == XFS_EXT_NORM ||
- got.br_state == XFS_EXT_UNWRITTEN);
- /*
- * Fall down into the found allocated space case.
- */
+ if (flist && flist->xbf_low)
+ minleft = 0;
+ if (bma.rval == NULLFSBLOCK)
+ break;
} else if (inhole) {
/*
* Reading in a hole.
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