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NFSv4.1: Replace dprintk() in pnfs_update_layout with something less buggy 

Dereferencing nfsi->layout in order to read plh_flags without holding
a spin lock is bug prone. Furthermore, the dprintk() tells you nothing
about whether or not the call succeeded.
Replace it with something that tells you about whether or not a valid
layout segment was returned for the inode in question.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2012-09-26 11:21:40 -04:00
parent 78e4e05c64
commit f86bbcf85d
1 changed files with 11 additions and 7 deletions
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18
fs/nfs/pnfs.c
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@ -1027,17 +1027,15 @@ pnfs_update_layout(struct inode *ino,
bool first = false;
if (!pnfs_enabled_sb(NFS_SERVER(ino)))
return NULL;
goto out;
if (pnfs_within_mdsthreshold(ctx, ino, iomode))
return NULL;
goto out;
spin_lock(&ino->i_lock);
lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
if (lo == NULL) {
dprintk("%s ERROR: can't get pnfs_layout_hdr\n", __func__);
if (lo == NULL)
goto out_unlock;
}
/* Do we even need to bother with this? */
if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
@ -1093,8 +1091,14 @@ pnfs_update_layout(struct inode *ino,
atomic_dec(&lo->plh_outstanding);
pnfs_put_layout_hdr(lo);
out:
dprintk("%s end, state 0x%lx lseg %p\n", __func__,
nfsi->layout ? nfsi->layout->plh_flags : -1, lseg);
dprintk("%s: inode %s/%llu pNFS layout segment %s for "
"(%s, offset: %llu, length: %llu)\n",
__func__, ino->i_sb->s_id,
(unsigned long long)NFS_FILEID(ino),
lseg == NULL ? "not found" : "found",
iomode==IOMODE_RW ? "read/write" : "read-only",
(unsigned long long)pos,
(unsigned long long)count);
return lseg;
out_unlock:
spin_unlock(&ino->i_lock);