diff options
| -rw-r--r-- | fs/autofs4/autofs_i.h | 4 | ||||
| -rw-r--r-- | fs/autofs4/inode.c | 9 | ||||
| -rw-r--r-- | fs/autofs4/root.c | 171 |
3 files changed, 161 insertions, 23 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h index 6b4cec3f272..d85f42fa920 100644 --- a/fs/autofs4/autofs_i.h +++ b/fs/autofs4/autofs_i.h @@ -52,6 +52,8 @@ struct autofs_info { int flags; + struct list_head rehash; + struct autofs_sb_info *sbi; unsigned long last_used; atomic_t count; @@ -110,6 +112,8 @@ struct autofs_sb_info { struct mutex wq_mutex; spinlock_t fs_lock; struct autofs_wait_queue *queues; /* Wait queue pointer */ + spinlock_t rehash_lock; + struct list_head rehash_list; }; static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb) diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c index 5e458e096ef..26063dc84a2 100644 --- a/fs/autofs4/inode.c +++ b/fs/autofs4/inode.c @@ -48,6 +48,8 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *ino, ino->dentry = NULL; ino->size = 0; + INIT_LIST_HEAD(&ino->rehash); + ino->last_used = jiffies; atomic_set(&ino->count, 0); @@ -158,14 +160,13 @@ void autofs4_kill_sb(struct super_block *sb) if (!sbi) goto out_kill_sb; - sb->s_fs_info = NULL; - - if ( !sbi->catatonic ) + if (!sbi->catatonic) autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */ /* Clean up and release dangling references */ autofs4_force_release(sbi); + sb->s_fs_info = NULL; kfree(sbi); out_kill_sb: @@ -336,6 +337,8 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent) mutex_init(&sbi->wq_mutex); spin_lock_init(&sbi->fs_lock); sbi->queues = NULL; + spin_lock_init(&sbi->rehash_lock); + INIT_LIST_HEAD(&sbi->rehash_list); s->s_blocksize = 1024; s->s_blocksize_bits = 10; s->s_magic = AUTOFS_SUPER_MAGIC; diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 47fee96c218..47adf270106 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -263,7 +263,7 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags) */ status = d_invalidate(dentry); if (status != -EBUSY) - return -ENOENT; + return -EAGAIN; } DPRINTK("dentry=%p %.*s ino=%p", @@ -413,7 +413,16 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) */ status = try_to_fill_dentry(dentry, flags); if (status == 0) - return 1; + return 1; + + /* + * A status of EAGAIN here means that the dentry has gone + * away while waiting for an expire to complete. If we are + * racing with expire lookup will wait for it so this must + * be a revalidate and we need to send it to lookup. + */ + if (status == -EAGAIN) + return 0; return status; } @@ -459,9 +468,18 @@ void autofs4_dentry_release(struct dentry *de) de->d_fsdata = NULL; if (inf) { + struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); + inf->dentry = NULL; inf->inode = NULL; + if (sbi) { + spin_lock(&sbi->rehash_lock); + if (!list_empty(&inf->rehash)) + list_del(&inf->rehash); + spin_unlock(&sbi->rehash_lock); + } + autofs4_free_ino(inf); } } @@ -478,10 +496,80 @@ static struct dentry_operations autofs4_dentry_operations = { .d_release = autofs4_dentry_release, }; +static struct dentry *autofs4_lookup_unhashed(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name) +{ + unsigned int len = name->len; + unsigned int hash = name->hash; + const unsigned char *str = name->name; + struct list_head *p, *head; + + spin_lock(&dcache_lock); + spin_lock(&sbi->rehash_lock); + head = &sbi->rehash_list; + list_for_each(p, head) { + struct autofs_info *ino; + struct dentry *dentry; + struct qstr *qstr; + + ino = list_entry(p, struct autofs_info, rehash); + dentry = ino->dentry; + + spin_lock(&dentry->d_lock); + + /* Bad luck, we've already been dentry_iput */ + if (!dentry->d_inode) + goto next; + + qstr = &dentry->d_name; + + if (dentry->d_name.hash != hash) + goto next; + if (dentry->d_parent != parent) + goto next; + + if (qstr->len != len) + goto next; + if (memcmp(qstr->name, str, len)) + goto next; + + if (d_unhashed(dentry)) { + struct autofs_info *ino = autofs4_dentry_ino(dentry); + struct inode *inode = dentry->d_inode; + + list_del_init(&ino->rehash); + dget(dentry); + /* + * Make the rehashed dentry negative so the VFS + * behaves as it should. + */ + if (inode) { + dentry->d_inode = NULL; + list_del_init(&dentry->d_alias); + spin_unlock(&dentry->d_lock); + spin_unlock(&sbi->rehash_lock); + spin_unlock(&dcache_lock); + iput(inode); + return dentry; + } + spin_unlock(&dentry->d_lock); + spin_unlock(&sbi->rehash_lock); + spin_unlock(&dcache_lock); + return dentry; + } +next: + spin_unlock(&dentry->d_lock); + } + spin_unlock(&sbi->rehash_lock); + spin_unlock(&dcache_lock); + + return NULL; +} + /* Lookups in the root directory */ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { struct autofs_sb_info *sbi; + struct dentry *unhashed; int oz_mode; DPRINTK("name = %.*s", @@ -497,25 +585,46 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", current->pid, process_group(current), sbi->catatonic, oz_mode); - /* - * Mark the dentry incomplete, but add it. This is needed so - * that the VFS layer knows about the dentry, and we can count - * on catching any lookups through the revalidate. - * - * Let all the hard work be done by the revalidate function that - * needs to be able to do this anyway.. - * - * We need to do this before we release the directory semaphore. - */ - dentry->d_op = &autofs4_root_dentry_operations; + unhashed = autofs4_lookup_unhashed(sbi, dentry->d_parent, &dentry->d_name); + if (!unhashed) { + /* + * Mark the dentry incomplete, but add it. This is needed so + * that the VFS layer knows about the dentry, and we can count + * on catching any lookups through the revalidate. + * + * Let all the hard work be done by the revalidate function that + * needs to be able to do this anyway.. + * + * We need to do this before we release the directory semaphore. + */ + dentry->d_op = &autofs4_root_dentry_operations; + + dentry->d_fsdata = NULL; + d_add(dentry, NULL); + } else { + struct autofs_info *ino = autofs4_dentry_ino(unhashed); + DPRINTK("rehash %p with %p", dentry, unhashed); + /* + * If we are racing with expire the request might not + * be quite complete but the directory has been removed + * so it must have been successful, so just wait for it. + */ + if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) { + DPRINTK("wait for incomplete expire %p name=%.*s", + unhashed, unhashed->d_name.len, + unhashed->d_name.name); + autofs4_wait(sbi, unhashed, NFY_NONE); + DPRINTK("request completed"); + } + d_rehash(unhashed); + dentry = unhashed; + } if (!oz_mode) { spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_AUTOFS_PENDING; spin_unlock(&dentry->d_lock); } - dentry->d_fsdata = NULL; - d_add(dentry, NULL); if (dentry->d_op && dentry->d_op->d_revalidate) { mutex_unlock(&dir->i_mutex); @@ -534,6 +643,8 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s if (sigismember (sigset, SIGKILL) || sigismember (sigset, SIGQUIT) || sigismember (sigset, SIGINT)) { + if (unhashed) + dput(unhashed); return ERR_PTR(-ERESTARTNOINTR); } } @@ -548,8 +659,14 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s * doesn't do the right thing for all system calls, but it should * be OK for the operations we permit from an autofs. */ - if (dentry->d_inode && d_unhashed(dentry)) + if (dentry->d_inode && d_unhashed(dentry)) { + if (unhashed) + dput(unhashed); return ERR_PTR(-ENOENT); + } + + if (unhashed) + return dentry; return NULL; } @@ -611,9 +728,10 @@ static int autofs4_dir_symlink(struct inode *dir, * Normal filesystems would do a "d_delete()" to tell the VFS dcache * that the file no longer exists. However, doing that means that the * VFS layer can turn the dentry into a negative dentry. We don't want - * this, because since the unlink is probably the result of an expire. - * We simply d_drop it, which allows the dentry lookup to remount it - * if necessary. + * this, because the unlink is probably the result of an expire. + * We simply d_drop it and add it to a rehash candidates list in the + * super block, which allows the dentry lookup to reuse it retaining + * the flags, such as expire in progress, in case we're racing with expire. * * If a process is blocked on the dentry waiting for the expire to finish, * it will invalidate the dentry and try to mount with a new one. @@ -642,7 +760,14 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) dir->i_mtime = CURRENT_TIME; - d_drop(dentry); + spin_lock(&dcache_lock); + spin_lock(&sbi->rehash_lock); + list_add(&ino->rehash, &sbi->rehash_list); + spin_unlock(&sbi->rehash_lock); + spin_lock(&dentry->d_lock); + __d_drop(dentry); + spin_unlock(&dentry->d_lock); + spin_unlock(&dcache_lock); return 0; } @@ -653,6 +778,9 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) struct autofs_info *ino = autofs4_dentry_ino(dentry); struct autofs_info *p_ino; + DPRINTK("dentry %p, removing %.*s", + dentry, dentry->d_name.len, dentry->d_name.name); + if (!autofs4_oz_mode(sbi)) return -EACCES; @@ -661,6 +789,9 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) spin_unlock(&dcache_lock); return -ENOTEMPTY; } + spin_lock(&sbi->rehash_lock); + list_add(&ino->rehash, &sbi->rehash_list); + spin_unlock(&sbi->rehash_lock); spin_lock(&dentry->d_lock); __d_drop(dentry); spin_unlock(&dentry->d_lock); |