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[PATCH] NFS: use atomic bitops to manipulate flags in nfsi->flags

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Introduce atomic bitops to manipulate the bits in the nfs_inode structure's
"flags" field.

Using bitops means we can use a generic wait_on_bit call instead of an ad hoc
locking scheme in fs/nfs/inode.c, so we can remove the "nfs_i_wait" field from
nfs_inode at the same time.

The other new flags field will continue to use bitmask and logic AND and OR.
This permits several flags to be set at the same time efficiently.  The
following patch adds a spin lock to protect these flags, and this spin lock
will later cover other fields in the nfs_inode structure, amortizing the cost
of using this type of serialization.

Test plan:
 Millions of fsx ops on SMP clients.

Signed-off-by: Chuck Lever <cel@netapp.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Chuck Lever 2005-08-18 11:24:11 -07:00 • committed by Linus Torvalds
parent 5529680981
commit 412d582ec1
3 changed files with 53 additions and 39 deletions
Download patch file Download diff file Expand all files Collapse all files

69
fs/nfs/inode.c
View file

@ -739,7 +739,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
inode->i_fop = &nfs_dir_operations;
if (nfs_server_capable(inode, NFS_CAP_READDIRPLUS)
&& fattr->size <= NFS_LIMIT_READDIRPLUS)
NFS_FLAGS(inode) |= NFS_INO_ADVISE_RDPLUS;
set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_FLAGS(inode));
} else if (S_ISLNK(inode->i_mode))
inode->i_op = &nfs_symlink_inode_operations;
else
@ -849,26 +849,43 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
}
}
static int nfs_wait_schedule(void *word)
{
if (signal_pending(current))
return -ERESTARTSYS;
schedule();
return 0;
}
/*
* Wait for the inode to get unlocked.
* (Used for NFS_INO_LOCKED and NFS_INO_REVALIDATING).
*/
static int
nfs_wait_on_inode(struct inode *inode, int flag)
static int nfs_wait_on_inode(struct inode *inode)
{
struct rpc_clnt *clnt = NFS_CLIENT(inode);
struct nfs_inode *nfsi = NFS_I(inode);
sigset_t oldmask;
int error;
if (!(NFS_FLAGS(inode) & flag))
return 0;
atomic_inc(&inode->i_count);
error = nfs_wait_event(clnt, nfsi->nfs_i_wait,
!(NFS_FLAGS(inode) & flag));
rpc_clnt_sigmask(clnt, &oldmask);
error = wait_on_bit_lock(&nfsi->flags, NFS_INO_REVALIDATING,
nfs_wait_schedule, TASK_INTERRUPTIBLE);
rpc_clnt_sigunmask(clnt, &oldmask);
iput(inode);
return error;
}
static void nfs_wake_up_inode(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
clear_bit(NFS_INO_REVALIDATING, &nfsi->flags);
smp_mb__after_clear_bit();
wake_up_bit(&nfsi->flags, NFS_INO_REVALIDATING);
}
int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
@ -1029,18 +1046,19 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
if (NFS_STALE(inode))
goto out_nowait;
while (NFS_REVALIDATING(inode)) {
status = nfs_wait_on_inode(inode, NFS_INO_REVALIDATING);
if (status < 0)
goto out_nowait;
if (NFS_ATTRTIMEO(inode) == 0)
continue;
if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA|NFS_INO_INVALID_ATIME))
continue;
status = NFS_STALE(inode) ? -ESTALE : 0;
goto out_nowait;
status = nfs_wait_on_inode(inode);
if (status < 0)
goto out;
if (NFS_STALE(inode)) {
status = -ESTALE;
/* Do we trust the cached ESTALE? */
if (NFS_ATTRTIMEO(inode) != 0) {
if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA|NFS_INO_INVALID_ATIME)) {
/* no */
} else
goto out;
}
}
NFS_FLAGS(inode) |= NFS_INO_REVALIDATING;
/* Protect against RPC races by saving the change attribute */
verifier = nfs_save_change_attribute(inode);
@ -1052,7 +1070,7 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
if (status == -ESTALE) {
nfs_zap_caches(inode);
if (!S_ISDIR(inode->i_mode))
NFS_FLAGS(inode) |= NFS_INO_STALE;
set_bit(NFS_INO_STALE, &NFS_FLAGS(inode));
}
goto out;
}
@ -1083,9 +1101,9 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
inode->i_sb->s_id,
(long long)NFS_FILEID(inode));
out:
NFS_FLAGS(inode) &= ~NFS_INO_REVALIDATING;
wake_up(&nfsi->nfs_i_wait);
out:
nfs_wake_up_inode(inode);
out_nowait:
unlock_kernel();
return status;
@ -1404,7 +1422,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr, unsign
*/
nfs_invalidate_inode(inode);
out_err:
NFS_FLAGS(inode) |= NFS_INO_STALE;
set_bit(NFS_INO_STALE, &NFS_FLAGS(inode));
return -ESTALE;
}
@ -1996,7 +2014,6 @@ static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
nfsi->ndirty = 0;
nfsi->ncommit = 0;
nfsi->npages = 0;
init_waitqueue_head(&nfsi->nfs_i_wait);
nfs4_init_once(nfsi);
}
}