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xfs: refactor xfs_ialloc_ag_select

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Loop over the in-core perag structures and prefer using pagi_freecount over
going out to the AGI buffer where possible.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
This commit is contained in:
Christoph Hellwig 2012-07-04 10:54:49 -04:00 committed by Ben Myers
parent 4bb61069d2
commit 55d6af64cb
1 changed files with 45 additions and 52 deletions
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97
fs/xfs/xfs_ialloc.c
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@ -442,14 +442,13 @@ xfs_ialloc_next_ag(
* Select an allocation group to look for a free inode in, based on the parent
* inode and then mode. Return the allocation group buffer.
*/
STATIC xfs_buf_t * /* allocation group buffer */
STATIC xfs_agnumber_t
xfs_ialloc_ag_select(
xfs_trans_t *tp, /* transaction pointer */
xfs_ino_t parent, /* parent directory inode number */
umode_t mode, /* bits set to indicate file type */
int okalloc) /* ok to allocate more space */
{
xfs_buf_t *agbp; /* allocation group header buffer */
xfs_agnumber_t agcount; /* number of ag's in the filesystem */
xfs_agnumber_t agno; /* current ag number */
int flags; /* alloc buffer locking flags */
@ -459,6 +458,7 @@ xfs_ialloc_ag_select(
int needspace; /* file mode implies space allocated */
xfs_perag_t *pag; /* per allocation group data */
xfs_agnumber_t pagno; /* parent (starting) ag number */
int error;
/*
* Files of these types need at least one block if length > 0
@ -474,7 +474,9 @@ xfs_ialloc_ag_select(
if (pagno >= agcount)
pagno = 0;
}
ASSERT(pagno < agcount);
/*
* Loop through allocation groups, looking for one with a little
* free space in it. Note we don't look for free inodes, exactly.
@ -486,51 +488,45 @@ xfs_ialloc_ag_select(
flags = XFS_ALLOC_FLAG_TRYLOCK;
for (;;) {
pag = xfs_perag_get(mp, agno);
if (!pag->pagi_init) {
if (xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
agbp = NULL;
goto nextag;
}
} else
agbp = NULL;
if (!pag->pagi_inodeok) {
xfs_ialloc_next_ag(mp);
goto unlock_nextag;
goto nextag;
}
if (!pag->pagi_init) {
error = xfs_ialloc_pagi_init(mp, tp, agno);
if (error)
goto nextag;
}
if (pag->pagi_freecount) {
xfs_perag_put(pag);
return agno;
}
if (!okalloc)
goto nextag;
if (!pag->pagf_init) {
error = xfs_alloc_pagf_init(mp, tp, agno, flags);
if (error)
goto nextag;
}
/*
* Is there enough free space for the file plus a block
* of inodes (if we need to allocate some)?
* Is there enough free space for the file plus a block of
* inodes? (if we need to allocate some)?
*/
ineed = pag->pagi_freecount ? 0 : XFS_IALLOC_BLOCKS(mp);
if (ineed && !pag->pagf_init) {
if (agbp == NULL &&
xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
agbp = NULL;
goto nextag;
}
(void)xfs_alloc_pagf_init(mp, tp, agno, flags);
ineed = XFS_IALLOC_BLOCKS(mp);
longest = pag->pagf_longest;
if (!longest)
longest = pag->pagf_flcount > 0;
if (pag->pagf_freeblks >= needspace + ineed &&
longest >= ineed) {
xfs_perag_put(pag);
return agno;
}
if (!ineed || pag->pagf_init) {
if (ineed && !(longest = pag->pagf_longest))
longest = pag->pagf_flcount > 0;
if (!ineed ||
(pag->pagf_freeblks >= needspace + ineed &&
longest >= ineed &&
okalloc)) {
if (agbp == NULL &&
xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
agbp = NULL;
goto nextag;
}
xfs_perag_put(pag);
return agbp;
}
}
unlock_nextag:
if (agbp)
xfs_trans_brelse(tp, agbp);
nextag:
xfs_perag_put(pag);
/*
@ -538,13 +534,13 @@ nextag:
* down.
*/
if (XFS_FORCED_SHUTDOWN(mp))
return NULL;
return NULLAGNUMBER;
agno++;
if (agno >= agcount)
agno = 0;
if (agno == pagno) {
if (flags == 0)
return NULL;
return NULLAGNUMBER;
flags = 0;
}
}
@ -901,13 +897,13 @@ xfs_dialloc(
struct xfs_buf **IO_agbp,
xfs_ino_t *inop)
{
struct xfs_mount *mp = tp->t_mountp;
struct xfs_buf *agbp;
xfs_agnumber_t agno;
struct xfs_agi *agi;
int error;
int ialloced;
int noroom = 0;
struct xfs_mount *mp;
xfs_agnumber_t tagno;
struct xfs_perag *pag;
@ -925,20 +921,17 @@ xfs_dialloc(
* We do not have an agbp, so select an initial allocation
* group for inode allocation.
*/
agbp = xfs_ialloc_ag_select(tp, parent, mode, okalloc);
/*
* Couldn't find an allocation group satisfying the
* criteria, give up.
*/
if (!agbp) {
agno = xfs_ialloc_ag_select(tp, parent, mode, okalloc);
if (agno == NULLAGNUMBER) {
*inop = NULLFSINO;
return 0;
}
error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
if (error)
return XFS_ERROR(error);
agi = XFS_BUF_TO_AGI(agbp);
mp = tp->t_mountp;
agno = be32_to_cpu(agi->agi_seqno);
tagno = agno;
/*