c698dbf9fe
Pull fs-cache fixes from David Howells: Can you pull these commits to fix an issue with NFS whereby caching can be enabled on a file that is open for writing by subsequently opening it for reading. This can be made to crash by opening it for writing again if you're quick enough. The gist of the patchset is that the cookie should be acquired at inode creation only and subsequently enabled and disabled as appropriate (which dispenses with the backing objects when they're not needed). The extra synchronisation that NFS does can then be dispensed with as it is thenceforth managed by FS-Cache. Could you send these on to Linus? This likely will need fixing also in CIFS and 9P also once the FS-Cache changes are upstream. AFS and Ceph are probably safe. * 'fscache' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: NFS: Use i_writecount to control whether to get an fscache cookie in nfs_open() FS-Cache: Provide the ability to enable/disable cookies FS-Cache: Add use/unuse/wake cookie wrappers
139 lines
3.1 KiB
C
139 lines
3.1 KiB
C
/*
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* linux/fs/nfs/file.c
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*
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* Copyright (C) 1992 Rick Sladkey
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*/
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#include <linux/nfs_fs.h>
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#include "internal.h"
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#include "fscache.h"
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#include "pnfs.h"
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#define NFSDBG_FACILITY NFSDBG_FILE
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static int
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nfs4_file_open(struct inode *inode, struct file *filp)
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{
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struct nfs_open_context *ctx;
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struct dentry *dentry = filp->f_path.dentry;
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struct dentry *parent = NULL;
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struct inode *dir;
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unsigned openflags = filp->f_flags;
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struct iattr attr;
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int opened = 0;
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int err;
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/*
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* If no cached dentry exists or if it's negative, NFSv4 handled the
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* opens in ->lookup() or ->create().
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*
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* We only get this far for a cached positive dentry. We skipped
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* revalidation, so handle it here by dropping the dentry and returning
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* -EOPENSTALE. The VFS will retry the lookup/create/open.
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*/
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dprintk("NFS: open file(%s/%s)\n",
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dentry->d_parent->d_name.name,
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dentry->d_name.name);
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if ((openflags & O_ACCMODE) == 3)
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openflags--;
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/* We can't create new files here */
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openflags &= ~(O_CREAT|O_EXCL);
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parent = dget_parent(dentry);
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dir = parent->d_inode;
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ctx = alloc_nfs_open_context(filp->f_path.dentry, filp->f_mode);
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err = PTR_ERR(ctx);
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if (IS_ERR(ctx))
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goto out;
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attr.ia_valid = ATTR_OPEN;
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if (openflags & O_TRUNC) {
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attr.ia_valid |= ATTR_SIZE;
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attr.ia_size = 0;
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nfs_wb_all(inode);
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}
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inode = NFS_PROTO(dir)->open_context(dir, ctx, openflags, &attr, &opened);
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if (IS_ERR(inode)) {
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err = PTR_ERR(inode);
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switch (err) {
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case -EPERM:
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case -EACCES:
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case -EDQUOT:
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case -ENOSPC:
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case -EROFS:
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goto out_put_ctx;
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default:
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goto out_drop;
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}
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}
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if (inode != dentry->d_inode)
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goto out_drop;
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nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
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nfs_file_set_open_context(filp, ctx);
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nfs_fscache_open_file(inode, filp);
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err = 0;
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out_put_ctx:
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put_nfs_open_context(ctx);
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out:
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dput(parent);
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return err;
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out_drop:
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d_drop(dentry);
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err = -EOPENSTALE;
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goto out_put_ctx;
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}
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static int
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nfs4_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
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{
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int ret;
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struct inode *inode = file_inode(file);
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do {
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ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
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if (ret != 0)
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break;
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mutex_lock(&inode->i_mutex);
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ret = nfs_file_fsync_commit(file, start, end, datasync);
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if (!ret && !datasync)
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/* application has asked for meta-data sync */
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ret = pnfs_layoutcommit_inode(inode, true);
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mutex_unlock(&inode->i_mutex);
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/*
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* If nfs_file_fsync_commit detected a server reboot, then
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* resend all dirty pages that might have been covered by
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* the NFS_CONTEXT_RESEND_WRITES flag
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*/
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start = 0;
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end = LLONG_MAX;
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} while (ret == -EAGAIN);
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return ret;
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}
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const struct file_operations nfs4_file_operations = {
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.llseek = nfs_file_llseek,
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.read = do_sync_read,
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.write = do_sync_write,
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.aio_read = nfs_file_read,
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.aio_write = nfs_file_write,
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.mmap = nfs_file_mmap,
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.open = nfs4_file_open,
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.flush = nfs_file_flush,
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.release = nfs_file_release,
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.fsync = nfs4_file_fsync,
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.lock = nfs_lock,
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.flock = nfs_flock,
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.splice_read = nfs_file_splice_read,
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.splice_write = nfs_file_splice_write,
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.check_flags = nfs_check_flags,
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.setlease = nfs_setlease,
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};
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