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xfs: fix min bufsize bugs in two places

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This fixes a bug in two places that I found by inspection.  In
xlog_find_verify_cycle() and xlog_write_log_records(), the code
attempts to allocate a buffer to hold as many blocks as possible.
It gives up if the number of blocks to be allocated gets too small.
Right now it uses log->l_sectbb_log as that lower bound, but I'm
sure it's supposed to be the actual log sector size instead.  That
is, the lower bound should be (1 << log->l_sectbb_log).

Also define a simple macro xlog_sectbb(log) to represent the number
of basic blocks in a sector for the given log.

(No change from original submission; I have implemented Christoph's
suggestion about storing l_sectsize rather than l_sectbb_log in
a new, separate patch in this series.)

Signed-off-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Alex Elder 2010-04-13 15:22:29 +10:00
parent a0e856b0b4
commit 6881a229f6
1 changed files with 17 additions and 4 deletions
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21
fs/xfs/xfs_log_recover.c
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@ -66,6 +66,9 @@ STATIC void xlog_recover_check_summary(xlog_t *);
((bbs + (log)->l_sectbb_mask + 1) & ~(log)->l_sectbb_mask) : (bbs) )
#define XLOG_SECTOR_ROUNDDOWN_BLKNO(log, bno) ((bno) & ~(log)->l_sectbb_mask)
/* Number of basic blocks in a log sector */
#define xlog_sectbb(log) (1 << (log)->l_sectbb_log)
STATIC xfs_buf_t *
xlog_get_bp(
xlog_t *log,
@ -376,12 +379,16 @@ xlog_find_verify_cycle(
xfs_caddr_t buf = NULL;
int error = 0;
/*
* Greedily allocate a buffer big enough to handle the full
* range of basic blocks we'll be examining. If that fails,
* try a smaller size. We need to be able to read at least
* a log sector, or we're out of luck.
*/
bufblks = 1 << ffs(nbblks);
while (!(bp = xlog_get_bp(log, bufblks))) {
/* can't get enough memory to do everything in one big buffer */
bufblks >>= 1;
if (bufblks <= log->l_sectbb_log)
if (bufblks < xlog_sectbb(log))
return ENOMEM;
}
@ -1158,10 +1165,16 @@ xlog_write_log_records(
int error = 0;
int i, j = 0;
/*
* Greedily allocate a buffer big enough to handle the full
* range of basic blocks to be written. If that fails, try
* a smaller size. We need to be able to write at least a
* log sector, or we're out of luck.
*/
bufblks = 1 << ffs(blocks);
while (!(bp = xlog_get_bp(log, bufblks))) {
bufblks >>= 1;
if (bufblks <= log->l_sectbb_log)
if (bufblks < xlog_sectbb(log))
return ENOMEM;
}