diff options
| -rw-r--r-- | fs/afs/cell.c | 12 | ||||
| -rw-r--r-- | fs/afs/dynroot.c | 124 | ||||
| -rw-r--r-- | fs/afs/internal.h | 7 | ||||
| -rw-r--r-- | fs/afs/main.c | 2 | ||||
| -rw-r--r-- | fs/afs/super.c | 52 | ||||
| -rw-r--r-- | fs/namei.c | 29 | ||||
| -rw-r--r-- | include/linux/namei.h | 1 |
7 files changed, 200 insertions, 27 deletions
diff --git a/fs/afs/cell.c b/fs/afs/cell.c index bb92b54..f3d0bef 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -15,6 +15,7 @@ #include <linux/dns_resolver.h> #include <linux/sched.h> #include <linux/inet.h> +#include <linux/namei.h> #include <keys/rxrpc-type.h> #include "internal.h" @@ -531,9 +532,11 @@ static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell) ret = afs_proc_cell_setup(cell); if (ret < 0) return ret; - spin_lock(&net->proc_cells_lock); + + mutex_lock(&net->proc_cells_lock); list_add_tail(&cell->proc_link, &net->proc_cells); - spin_unlock(&net->proc_cells_lock); + afs_dynroot_mkdir(net, cell); + mutex_unlock(&net->proc_cells_lock); return 0; } @@ -546,9 +549,10 @@ static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell) afs_proc_cell_remove(cell); - spin_lock(&net->proc_cells_lock); + mutex_lock(&net->proc_cells_lock); list_del_init(&cell->proc_link); - spin_unlock(&net->proc_cells_lock); + afs_dynroot_rmdir(net, cell); + mutex_unlock(&net->proc_cells_lock); #ifdef CONFIG_AFS_FSCACHE fscache_relinquish_cookie(cell->cache, NULL, false); diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c index 7425f416..174e843 100644 --- a/fs/afs/dynroot.c +++ b/fs/afs/dynroot.c @@ -1,4 +1,4 @@ -/* dir.c: AFS dynamic root handling +/* AFS dynamic root handling * * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) @@ -207,3 +207,125 @@ const struct dentry_operations afs_dynroot_dentry_operations = { .d_release = afs_d_release, .d_automount = afs_d_automount, }; + +/* + * Create a manually added cell mount directory. + * - The caller must hold net->proc_cells_lock + */ +int afs_dynroot_mkdir(struct afs_net *net, struct afs_cell *cell) +{ + struct super_block *sb = net->dynroot_sb; + struct dentry *root, *subdir; + int ret; + + if (!sb || atomic_read(&sb->s_active) == 0) + return 0; + + /* Let the ->lookup op do the creation */ + root = sb->s_root; + inode_lock(root->d_inode); + subdir = lookup_one_len(cell->name, root, cell->name_len); + if (IS_ERR(subdir)) { + ret = PTR_ERR(subdir); + goto unlock; + } + + /* Note that we're retaining an extra ref on the dentry */ + subdir->d_fsdata = (void *)1UL; + ret = 0; +unlock: + inode_unlock(root->d_inode); + return ret; +} + +/* + * Remove a manually added cell mount directory. + * - The caller must hold net->proc_cells_lock + */ +void afs_dynroot_rmdir(struct afs_net *net, struct afs_cell *cell) +{ + struct super_block *sb = net->dynroot_sb; + struct dentry *root, *subdir; + + if (!sb || atomic_read(&sb->s_active) == 0) + return; + + root = sb->s_root; + inode_lock(root->d_inode); + + /* Don't want to trigger a lookup call, which will re-add the cell */ + subdir = try_lookup_one_len(cell->name, root, cell->name_len); + if (IS_ERR_OR_NULL(subdir)) { + _debug("lookup %ld", PTR_ERR(subdir)); + goto no_dentry; + } + + _debug("rmdir %pd %u", subdir, d_count(subdir)); + + if (subdir->d_fsdata) { + _debug("unpin %u", d_count(subdir)); + subdir->d_fsdata = NULL; + dput(subdir); + } + dput(subdir); +no_dentry: + inode_unlock(root->d_inode); + _leave(""); +} + +/* + * Populate a newly created dynamic root with cell names. + */ +int afs_dynroot_populate(struct super_block *sb) +{ + struct afs_cell *cell; + struct afs_net *net = afs_sb2net(sb); + int ret; + + if (mutex_lock_interruptible(&net->proc_cells_lock) < 0) + return -ERESTARTSYS; + + net->dynroot_sb = sb; + list_for_each_entry(cell, &net->proc_cells, proc_link) { + ret = afs_dynroot_mkdir(net, cell); + if (ret < 0) + goto error; + } + + ret = 0; +out: + mutex_unlock(&net->proc_cells_lock); + return ret; + +error: + net->dynroot_sb = NULL; + goto out; +} + +/* + * When a dynamic root that's in the process of being destroyed, depopulate it + * of pinned directories. + */ +void afs_dynroot_depopulate(struct super_block *sb) +{ + struct afs_net *net = afs_sb2net(sb); + struct dentry *root = sb->s_root, *subdir, *tmp; + + /* Prevent more subdirs from being created */ + mutex_lock(&net->proc_cells_lock); + if (net->dynroot_sb == sb) + net->dynroot_sb = NULL; + mutex_unlock(&net->proc_cells_lock); + + inode_lock(root->d_inode); + + /* Remove all the pins for dirs created for manually added cells */ + list_for_each_entry_safe(subdir, tmp, &root->d_subdirs, d_child) { + if (subdir->d_fsdata) { + subdir->d_fsdata = NULL; + dput(subdir); + } + } + + inode_unlock(root->d_inode); +} diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 209e04f..5d8260b 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -240,7 +240,7 @@ struct afs_net { atomic_t cells_outstanding; seqlock_t cells_lock; - spinlock_t proc_cells_lock; + struct mutex proc_cells_lock; struct list_head proc_cells; /* Known servers. Theoretically each fileserver can only be in one @@ -264,6 +264,7 @@ struct afs_net { struct mutex lock_manager_mutex; /* Misc */ + struct super_block *dynroot_sb; /* Dynamic root mount superblock */ struct proc_dir_entry *proc_afs; /* /proc/net/afs directory */ struct afs_sysnames *sysnames; rwlock_t sysnames_lock; @@ -722,6 +723,10 @@ extern const struct inode_operations afs_dynroot_inode_operations; extern const struct dentry_operations afs_dynroot_dentry_operations; extern struct inode *afs_try_auto_mntpt(struct dentry *, struct inode *); +extern int afs_dynroot_mkdir(struct afs_net *, struct afs_cell *); +extern void afs_dynroot_rmdir(struct afs_net *, struct afs_cell *); +extern int afs_dynroot_populate(struct super_block *); +extern void afs_dynroot_depopulate(struct super_block *); /* * file.c diff --git a/fs/afs/main.c b/fs/afs/main.c index 7d2c135..e84fe82 100644 --- a/fs/afs/main.c +++ b/fs/afs/main.c @@ -86,7 +86,7 @@ static int __net_init afs_net_init(struct net *net_ns) INIT_WORK(&net->cells_manager, afs_manage_cells); timer_setup(&net->cells_timer, afs_cells_timer, 0); - spin_lock_init(&net->proc_cells_lock); + mutex_init(&net->proc_cells_lock); INIT_LIST_HEAD(&net->proc_cells); seqlock_init(&net->fs_lock); diff --git a/fs/afs/super.c b/fs/afs/super.c index 8707d86..4d3e274 100644 --- a/fs/afs/super.c +++ b/fs/afs/super.c @@ -355,12 +355,17 @@ static int afs_test_super(struct super_block *sb, void *data) return (as->net_ns == as1->net_ns && as->volume && - as->volume->vid == as1->volume->vid); + as->volume->vid == as1->volume->vid && + !as->dyn_root); } static int afs_dynroot_test_super(struct super_block *sb, void *data) { - return false; + struct afs_super_info *as1 = data; + struct afs_super_info *as = AFS_FS_S(sb); + + return (as->net_ns == as1->net_ns && + as->dyn_root); } static int afs_set_super(struct super_block *sb, void *data) @@ -420,10 +425,14 @@ static int afs_fill_super(struct super_block *sb, if (!sb->s_root) goto error; - if (params->dyn_root) + if (as->dyn_root) { sb->s_d_op = &afs_dynroot_dentry_operations; - else + ret = afs_dynroot_populate(sb); + if (ret < 0) + goto error; + } else { sb->s_d_op = &afs_fs_dentry_operations; + } _leave(" = 0"); return 0; @@ -458,6 +467,25 @@ static void afs_destroy_sbi(struct afs_super_info *as) } } +static void afs_kill_super(struct super_block *sb) +{ + struct afs_super_info *as = AFS_FS_S(sb); + struct afs_net *net = afs_net(as->net_ns); + + if (as->dyn_root) + afs_dynroot_depopulate(sb); + + /* Clear the callback interests (which will do ilookup5) before + * deactivating the superblock. + */ + if (as->volume) + afs_clear_callback_interests(net, as->volume->servers); + kill_anon_super(sb); + if (as->volume) + afs_deactivate_volume(as->volume); + afs_destroy_sbi(as); +} + /* * get an AFS superblock */ @@ -566,22 +594,6 @@ error: return ERR_PTR(ret); } -static void afs_kill_super(struct super_block *sb) -{ - struct afs_super_info *as = AFS_FS_S(sb); - - /* Clear the callback interests (which will do ilookup5) before - * deactivating the superblock. - */ - if (as->volume) - afs_clear_callback_interests(afs_net(as->net_ns), - as->volume->servers); - kill_anon_super(sb); - if (as->volume) - afs_deactivate_volume(as->volume); - afs_destroy_sbi(as); -} - /* * Initialise an inode cache slab element prior to any use. Note that * afs_alloc_inode() *must* reset anything that could incorrectly leak from one @@ -2464,6 +2464,35 @@ static int lookup_one_len_common(const char *name, struct dentry *base, } /** + * try_lookup_one_len - filesystem helper to lookup single pathname component + * @name: pathname component to lookup + * @base: base directory to lookup from + * @len: maximum length @len should be interpreted to + * + * Look up a dentry by name in the dcache, returning NULL if it does not + * currently exist. The function does not try to create a dentry. + * + * Note that this routine is purely a helper for filesystem usage and should + * not be called by generic code. + * + * The caller must hold base->i_mutex. + */ +struct dentry *try_lookup_one_len(const char *name, struct dentry *base, int len) +{ + struct qstr this; + int err; + + WARN_ON_ONCE(!inode_is_locked(base->d_inode)); + + err = lookup_one_len_common(name, base, len, &this); + if (err) + return ERR_PTR(err); + + return lookup_dcache(&this, base, 0); +} +EXPORT_SYMBOL(try_lookup_one_len); + +/** * lookup_one_len - filesystem helper to lookup single pathname component * @name: pathname component to lookup * @base: base directory to lookup from diff --git a/include/linux/namei.h b/include/linux/namei.h index a982bb7..a78606e 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -81,6 +81,7 @@ extern void done_path_create(struct path *, struct dentry *); extern struct dentry *kern_path_locked(const char *, struct path *); extern int kern_path_mountpoint(int, const char *, struct path *, unsigned int); +extern struct dentry *try_lookup_one_len(const char *, struct dentry *, int); extern struct dentry *lookup_one_len(const char *, struct dentry *, int); extern struct dentry *lookup_one_len_unlocked(const char *, struct dentry *, int); |
