linux/fs/nfs/nfs4file.c
Trond Myklebust 5445b1fbd1 NFSv4: Respect the server imposed limit on how many changes we may cache
The NFSv4 delegation spec allows the server to tell a client to limit how
much data it cache after the file is closed. In return, the server
guarantees enough free space to avoid ENOSPC situations, etc.
Prior to this patch, we assumed we could always cache aggressively after
close. Unfortunately, this causes problems with servers that set the
limit to 0 and therefore do not offer any ENOSPC guarantees.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-09-07 12:36:17 -04:00

220 lines
4.8 KiB
C

/*
* linux/fs/nfs/file.c
*
* Copyright (C) 1992 Rick Sladkey
*/
#include <linux/fs.h>
#include <linux/falloc.h>
#include <linux/nfs_fs.h>
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "fscache.h"
#include "pnfs.h"
#include "nfstrace.h"
#ifdef CONFIG_NFS_V4_2
#include "nfs42.h"
#endif
#define NFSDBG_FACILITY NFSDBG_FILE
static int
nfs4_file_open(struct inode *inode, struct file *filp)
{
struct nfs_open_context *ctx;
struct dentry *dentry = filp->f_path.dentry;
struct dentry *parent = NULL;
struct inode *dir;
unsigned openflags = filp->f_flags;
struct iattr attr;
int err;
/*
* If no cached dentry exists or if it's negative, NFSv4 handled the
* opens in ->lookup() or ->create().
*
* We only get this far for a cached positive dentry. We skipped
* revalidation, so handle it here by dropping the dentry and returning
* -EOPENSTALE. The VFS will retry the lookup/create/open.
*/
dprintk("NFS: open file(%pd2)\n", dentry);
err = nfs_check_flags(openflags);
if (err)
return err;
if ((openflags & O_ACCMODE) == 3)
openflags--;
/* We can't create new files here */
openflags &= ~(O_CREAT|O_EXCL);
parent = dget_parent(dentry);
dir = d_inode(parent);
ctx = alloc_nfs_open_context(filp->f_path.dentry, filp->f_mode);
err = PTR_ERR(ctx);
if (IS_ERR(ctx))
goto out;
attr.ia_valid = ATTR_OPEN;
if (openflags & O_TRUNC) {
attr.ia_valid |= ATTR_SIZE;
attr.ia_size = 0;
nfs_sync_inode(inode);
}
inode = NFS_PROTO(dir)->open_context(dir, ctx, openflags, &attr, NULL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
switch (err) {
case -EPERM:
case -EACCES:
case -EDQUOT:
case -ENOSPC:
case -EROFS:
goto out_put_ctx;
default:
goto out_drop;
}
}
if (inode != d_inode(dentry))
goto out_drop;
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
nfs_file_set_open_context(filp, ctx);
nfs_fscache_open_file(inode, filp);
err = 0;
out_put_ctx:
put_nfs_open_context(ctx);
out:
dput(parent);
return err;
out_drop:
d_drop(dentry);
err = -EOPENSTALE;
goto out_put_ctx;
}
/*
* Flush all dirty pages, and check for write errors.
*/
static int
nfs4_file_flush(struct file *file, fl_owner_t id)
{
struct inode *inode = file_inode(file);
dprintk("NFS: flush(%pD2)\n", file);
nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
if ((file->f_mode & FMODE_WRITE) == 0)
return 0;
/*
* If we're holding a write delegation, then check if we're required
* to flush the i/o on close. If not, then just start the i/o now.
*/
if (!nfs4_delegation_flush_on_close(inode))
return filemap_fdatawrite(file->f_mapping);
/* Flush writes to the server and return any errors */
return vfs_fsync(file, 0);
}
static int
nfs4_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
int ret;
struct inode *inode = file_inode(file);
trace_nfs_fsync_enter(inode);
nfs_inode_dio_wait(inode);
do {
ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (ret != 0)
break;
mutex_lock(&inode->i_mutex);
ret = nfs_file_fsync_commit(file, start, end, datasync);
if (!ret)
ret = pnfs_sync_inode(inode, !!datasync);
mutex_unlock(&inode->i_mutex);
/*
* If nfs_file_fsync_commit detected a server reboot, then
* resend all dirty pages that might have been covered by
* the NFS_CONTEXT_RESEND_WRITES flag
*/
start = 0;
end = LLONG_MAX;
} while (ret == -EAGAIN);
trace_nfs_fsync_exit(inode, ret);
return ret;
}
#ifdef CONFIG_NFS_V4_2
static loff_t nfs4_file_llseek(struct file *filep, loff_t offset, int whence)
{
loff_t ret;
switch (whence) {
case SEEK_HOLE:
case SEEK_DATA:
ret = nfs42_proc_llseek(filep, offset, whence);
if (ret != -ENOTSUPP)
return ret;
default:
return nfs_file_llseek(filep, offset, whence);
}
}
static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t len)
{
struct inode *inode = file_inode(filep);
long ret;
if (!S_ISREG(inode->i_mode))
return -EOPNOTSUPP;
if ((mode != 0) && (mode != (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE)))
return -EOPNOTSUPP;
ret = inode_newsize_ok(inode, offset + len);
if (ret < 0)
return ret;
if (mode & FALLOC_FL_PUNCH_HOLE)
return nfs42_proc_deallocate(filep, offset, len);
return nfs42_proc_allocate(filep, offset, len);
}
#endif /* CONFIG_NFS_V4_2 */
const struct file_operations nfs4_file_operations = {
#ifdef CONFIG_NFS_V4_2
.llseek = nfs4_file_llseek,
#else
.llseek = nfs_file_llseek,
#endif
.read_iter = nfs_file_read,
.write_iter = nfs_file_write,
.mmap = nfs_file_mmap,
.open = nfs4_file_open,
.flush = nfs4_file_flush,
.release = nfs_file_release,
.fsync = nfs4_file_fsync,
.lock = nfs_lock,
.flock = nfs_flock,
.splice_read = nfs_file_splice_read,
.splice_write = iter_file_splice_write,
#ifdef CONFIG_NFS_V4_2
.fallocate = nfs42_fallocate,
#endif /* CONFIG_NFS_V4_2 */
.check_flags = nfs_check_flags,
.setlease = simple_nosetlease,
};