diff options
Diffstat (limited to 'fs/9p/vfs_dentry.c')
| -rw-r--r-- | fs/9p/vfs_dentry.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c new file mode 100644 index 000000000..fa6b7143d --- /dev/null +++ b/fs/9p/vfs_dentry.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This file contians vfs dentry ops for the 9P2000 protocol. + * + * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> + * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> + */ + +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <linux/pagemap.h> +#include <linux/stat.h> +#include <linux/string.h> +#include <linux/namei.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <net/9p/9p.h> +#include <net/9p/client.h> + +#include "v9fs.h" +#include "v9fs_vfs.h" +#include "fid.h" + +/** + * v9fs_ndentry_is_expired - Check if negative dentry lookup has expired + * + * This should be called to know if a negative dentry should be removed from + * cache. + * + * @dentry: dentry in question + * + */ +static bool v9fs_ndentry_is_expired(struct dentry const *dentry) +{ + struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry); + struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry); + + if (v9ses->ndentry_timeout_ms == NDENTRY_TIMEOUT_NEVER) + return false; + + return time_before_eq64(v9fs_dentry->expire_time, get_jiffies_64()); +} + +/** + * v9fs_ndentry_refresh_timeout - Refresh negative dentry lookup cache timeout + * + * This should be called when a look up yields a negative entry. + * + * @dentry: dentry in question + * + */ +void v9fs_ndentry_refresh_timeout(struct dentry *dentry) +{ + struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry); + struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry); + + if (v9ses->ndentry_timeout_ms == NDENTRY_TIMEOUT_NEVER) + return; + + v9fs_dentry->expire_time = get_jiffies_64() + + msecs_to_jiffies(v9ses->ndentry_timeout_ms); +} + +/** + * v9fs_cached_dentry_delete - called when dentry refcount equals 0 + * @dentry: dentry in question + * + */ +static int v9fs_cached_dentry_delete(const struct dentry *dentry) +{ + p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n", + dentry, dentry); + + if (!d_really_is_negative(dentry)) + return 0; + + return v9fs_ndentry_is_expired(dentry); +} + +static void __v9fs_dentry_fid_remove(struct dentry *dentry) +{ + struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry); + struct hlist_node *p, *n; + struct hlist_head head; + + p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n", + dentry, dentry); + + spin_lock(&dentry->d_lock); + hlist_move_list(&v9fs_dentry->head, &head); + spin_unlock(&dentry->d_lock); + + hlist_for_each_safe(p, n, &head) + p9_fid_put(hlist_entry(p, struct p9_fid, dlist)); +} + +/** + * v9fs_dentry_fid_remove - Release all dentry's fids + * @dentry: dentry in question + * + */ +void v9fs_dentry_fid_remove(struct dentry *dentry) +{ + __v9fs_dentry_fid_remove(dentry); +} + +/** + * v9fs_dentry_init - Initialize v9fs dentry data + * @dentry: dentry in question + * + */ +static int v9fs_dentry_init(struct dentry *dentry) +{ + struct v9fs_dentry *v9fs_dentry = kzalloc_obj(*v9fs_dentry); + + if (!v9fs_dentry) + return -ENOMEM; + + INIT_HLIST_HEAD(&v9fs_dentry->head); + dentry->d_fsdata = (void *)v9fs_dentry; + return 0; +} + +/** + * v9fs_dentry_release - called when dentry is going to be freed + * @dentry: dentry that is being released + * + */ +static void v9fs_dentry_release(struct dentry *dentry) +{ + struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry); + + __v9fs_dentry_fid_remove(dentry); + kfree_rcu(v9fs_dentry, rcu); +} + +static int __v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct p9_fid *fid; + struct inode *inode; + struct v9fs_inode *v9inode; + + if (flags & LOOKUP_RCU) + return -ECHILD; + + inode = d_inode(dentry); + if (!inode) + return !v9fs_ndentry_is_expired(dentry); + + v9inode = V9FS_I(inode); + if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) { + int retval; + struct v9fs_session_info *v9ses; + + fid = v9fs_fid_lookup(dentry); + if (IS_ERR(fid)) { + p9_debug( + P9_DEBUG_VFS, + "v9fs_fid_lookup: dentry = %pd (%p), got error %pe\n", + dentry, dentry, fid); + return PTR_ERR(fid); + } + + v9ses = v9fs_inode2v9ses(inode); + if (v9fs_proto_dotl(v9ses)) + retval = v9fs_refresh_inode_dotl(fid, inode); + else + retval = v9fs_refresh_inode(fid, inode); + p9_fid_put(fid); + + if (retval == -ENOENT) { + p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to ENOENT\n", + dentry, dentry); + return 0; + } + if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) { + p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) invalidated due to type change\n", + dentry, dentry); + return 0; + } + if (retval < 0) { + p9_debug(P9_DEBUG_VFS, + "refresh inode: dentry = %pd (%p), got error %pe\n", + dentry, dentry, ERR_PTR(retval)); + return retval; + } + } + p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) is valid\n", dentry, dentry); + return 1; +} + +static int v9fs_lookup_revalidate(struct inode *dir, const struct qstr *name, + struct dentry *dentry, unsigned int flags) +{ + return __v9fs_lookup_revalidate(dentry, flags); +} + +static bool v9fs_dentry_unalias_trylock(const struct dentry *dentry) +{ + struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry); + return down_write_trylock(&v9ses->rename_sem); +} + +static void v9fs_dentry_unalias_unlock(const struct dentry *dentry) +{ + struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry); + up_write(&v9ses->rename_sem); +} + +const struct dentry_operations v9fs_cached_dentry_operations = { + .d_revalidate = v9fs_lookup_revalidate, + .d_weak_revalidate = __v9fs_lookup_revalidate, + .d_delete = v9fs_cached_dentry_delete, + .d_init = v9fs_dentry_init, + .d_release = v9fs_dentry_release, + .d_unalias_trylock = v9fs_dentry_unalias_trylock, + .d_unalias_unlock = v9fs_dentry_unalias_unlock, +}; + +const struct dentry_operations v9fs_dentry_operations = { + .d_init = v9fs_dentry_init, + .d_release = v9fs_dentry_release, + .d_unalias_trylock = v9fs_dentry_unalias_trylock, + .d_unalias_unlock = v9fs_dentry_unalias_unlock, +}; |