diff options
Diffstat (limited to 'fs/nfs/dir.c')
| -rw-r--r-- | fs/nfs/dir.c | 126 |
1 files changed, 116 insertions, 10 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 1320288ff9ec..193d6fb363b7 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -155,6 +155,7 @@ typedef struct { loff_t current_index; decode_dirent_t decode; + unsigned long dir_verifier; unsigned long timestamp; unsigned long gencount; unsigned int cache_entry_index; @@ -353,6 +354,7 @@ int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc, again: timestamp = jiffies; gencount = nfs_inc_attr_generation_counter(); + desc->dir_verifier = nfs_save_change_attribute(inode); error = NFS_PROTO(inode)->readdir(file_dentry(file), cred, entry->cookie, pages, NFS_SERVER(inode)->dtsize, desc->plus); if (error < 0) { @@ -455,13 +457,13 @@ void nfs_force_use_readdirplus(struct inode *dir) } static -void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry) +void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry, + unsigned long dir_verifier) { struct qstr filename = QSTR_INIT(entry->name, entry->len); DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); struct dentry *dentry; struct dentry *alias; - struct inode *dir = d_inode(parent); struct inode *inode; int status; @@ -500,7 +502,7 @@ again: if (nfs_same_file(dentry, entry)) { if (!entry->fh->size) goto out; - nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + nfs_set_verifier(dentry, dir_verifier); status = nfs_refresh_inode(d_inode(dentry), entry->fattr); if (!status) nfs_setsecurity(d_inode(dentry), entry->fattr, entry->label); @@ -526,7 +528,7 @@ again: dput(dentry); dentry = alias; } - nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + nfs_set_verifier(dentry, dir_verifier); out: dput(dentry); } @@ -564,7 +566,8 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en count++; if (desc->plus) - nfs_prime_dcache(file_dentry(desc->file), entry); + nfs_prime_dcache(file_dentry(desc->file), entry, + desc->dir_verifier); status = nfs_readdir_add_to_array(entry, page); if (status != 0) @@ -983,14 +986,113 @@ static int nfs_fsync_dir(struct file *filp, loff_t start, loff_t end, * full lookup on all child dentries of 'dir' whenever a change occurs * on the server that might have invalidated our dcache. * + * Note that we reserve bit '0' as a tag to let us know when a dentry + * was revalidated while holding a delegation on its inode. + * * The caller should be holding dir->i_lock */ void nfs_force_lookup_revalidate(struct inode *dir) { - NFS_I(dir)->cache_change_attribute++; + NFS_I(dir)->cache_change_attribute += 2; } EXPORT_SYMBOL_GPL(nfs_force_lookup_revalidate); +/** + * nfs_verify_change_attribute - Detects NFS remote directory changes + * @dir: pointer to parent directory inode + * @verf: previously saved change attribute + * + * Return "false" if the verifiers doesn't match the change attribute. + * This would usually indicate that the directory contents have changed on + * the server, and that any dentries need revalidating. + */ +static bool nfs_verify_change_attribute(struct inode *dir, unsigned long verf) +{ + return (verf & ~1UL) == nfs_save_change_attribute(dir); +} + +static void nfs_set_verifier_delegated(unsigned long *verf) +{ + *verf |= 1UL; +} + +#if IS_ENABLED(CONFIG_NFS_V4) +static void nfs_unset_verifier_delegated(unsigned long *verf) +{ + *verf &= ~1UL; +} +#endif /* IS_ENABLED(CONFIG_NFS_V4) */ + +static bool nfs_test_verifier_delegated(unsigned long verf) +{ + return verf & 1; +} + +static bool nfs_verifier_is_delegated(struct dentry *dentry) +{ + return nfs_test_verifier_delegated(dentry->d_time); +} + +static void nfs_set_verifier_locked(struct dentry *dentry, unsigned long verf) +{ + struct inode *inode = d_inode(dentry); + + if (!nfs_verifier_is_delegated(dentry) && + !nfs_verify_change_attribute(d_inode(dentry->d_parent), verf)) + goto out; + if (inode && NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) + nfs_set_verifier_delegated(&verf); +out: + dentry->d_time = verf; +} + +/** + * nfs_set_verifier - save a parent directory verifier in the dentry + * @dentry: pointer to dentry + * @verf: verifier to save + * + * Saves the parent directory verifier in @dentry. If the inode has + * a delegation, we also tag the dentry as having been revalidated + * while holding a delegation so that we know we don't have to + * look it up again after a directory change. + */ +void nfs_set_verifier(struct dentry *dentry, unsigned long verf) +{ + + spin_lock(&dentry->d_lock); + nfs_set_verifier_locked(dentry, verf); + spin_unlock(&dentry->d_lock); +} +EXPORT_SYMBOL_GPL(nfs_set_verifier); + +#if IS_ENABLED(CONFIG_NFS_V4) +/** + * nfs_clear_verifier_delegated - clear the dir verifier delegation tag + * @inode: pointer to inode + * + * Iterates through the dentries in the inode alias list and clears + * the tag used to indicate that the dentry has been revalidated + * while holding a delegation. + * This function is intended for use when the delegation is being + * returned or revoked. + */ +void nfs_clear_verifier_delegated(struct inode *inode) +{ + struct dentry *alias; + + if (!inode) + return; + spin_lock(&inode->i_lock); + hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { + spin_lock(&alias->d_lock); + nfs_unset_verifier_delegated(&alias->d_time); + spin_unlock(&alias->d_lock); + } + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL_GPL(nfs_clear_verifier_delegated); +#endif /* IS_ENABLED(CONFIG_NFS_V4) */ + /* * A check for whether or not the parent directory has changed. * In the case it has, we assume that the dentries are untrustworthy @@ -1159,6 +1261,7 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry, struct nfs_fh *fhandle; struct nfs_fattr *fattr; struct nfs4_label *label; + unsigned long dir_verifier; int ret; ret = -ENOMEM; @@ -1168,6 +1271,7 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry, if (fhandle == NULL || fattr == NULL || IS_ERR(label)) goto out; + dir_verifier = nfs_save_change_attribute(dir); ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label); if (ret < 0) { switch (ret) { @@ -1188,7 +1292,7 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry, goto out; nfs_setsecurity(inode, fattr, label); - nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + nfs_set_verifier(dentry, dir_verifier); /* set a readdirplus hint that we had a cache miss */ nfs_force_use_readdirplus(dir); @@ -1230,7 +1334,7 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, goto out_bad; } - if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ)) + if (nfs_verifier_is_delegated(dentry)) return nfs_lookup_revalidate_delegated(dir, dentry, inode); /* Force a full look up iff the parent directory has changed */ @@ -1415,6 +1519,7 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in struct nfs_fh *fhandle = NULL; struct nfs_fattr *fattr = NULL; struct nfs4_label *label = NULL; + unsigned long dir_verifier; int error; dfprintk(VFS, "NFS: lookup(%pd2)\n", dentry); @@ -1440,6 +1545,7 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in if (IS_ERR(label)) goto out; + dir_verifier = nfs_save_change_attribute(dir); trace_nfs_lookup_enter(dir, dentry, flags); error = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr, label); if (error == -ENOENT) @@ -1463,7 +1569,7 @@ no_entry: goto out_label; dentry = res; } - nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); + nfs_set_verifier(dentry, dir_verifier); out_label: trace_nfs_lookup_exit(dir, dentry, flags, error); nfs4_label_free(label); @@ -1668,7 +1774,7 @@ nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry, if (inode == NULL) goto full_reval; - if (NFS_PROTO(dir)->have_delegation(inode, FMODE_READ)) + if (nfs_verifier_is_delegated(dentry)) return nfs_lookup_revalidate_delegated(dir, dentry, inode); /* NFS only supports OPEN on regular files */ |