From 51eb01e73599efb88c6c20b1c226d20309a75450 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:50 -0700 Subject: [PATCH] fuse: no backgrounding on interrupt Don't put requests into the background when a fatal interrupt occurs while the request is in userspace. This removes a major wart from the implementation. Backgrounding of requests was introduced to allow breaking of deadlocks. However now the same can be achieved by aborting the filesystem through the 'abort' sysfs attribute. This is a change in the interface, but should not cause problems, since these kinds of deadlocks never happen during normal operation. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/fuse_i.h | 49 +++++++++++++------------------------------------ 1 file changed, 13 insertions(+), 36 deletions(-) (limited to 'fs/fuse/fuse_i.h') diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 0474202cb5dc..25f8581a770c 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -8,12 +8,12 @@ #include #include +#include #include #include #include #include #include -#include /** Max number of pages that can be used in a single read request */ #define FUSE_MAX_PAGES_PER_REQ 32 @@ -135,9 +135,6 @@ struct fuse_req { fuse_conn */ struct list_head list; - /** Entry on the background list */ - struct list_head bg_entry; - /** refcount */ atomic_t count; @@ -150,6 +147,9 @@ struct fuse_req { /** True if the request has reply */ unsigned isreply:1; + /** Force sending of the request even if interrupted */ + unsigned force:1; + /** The request was interrupted */ unsigned interrupted:1; @@ -192,15 +192,15 @@ struct fuse_req { /** offset of data on first page */ unsigned page_offset; - /** Inode used in the request */ - struct inode *inode; - - /** Second inode used in the request (or NULL) */ - struct inode *inode2; - /** File used in the request (or NULL) */ struct file *file; + /** vfsmount used in release */ + struct vfsmount *vfsmount; + + /** dentry used in release */ + struct dentry *dentry; + /** Request completion callback */ void (*end)(struct fuse_conn *, struct fuse_req *); }; @@ -243,10 +243,6 @@ struct fuse_conn { /** The list of requests under I/O */ struct list_head io; - /** Requests put in the background (RELEASE or any other - interrupted request) */ - struct list_head background; - /** Number of requests currently in the background */ unsigned num_background; @@ -258,15 +254,9 @@ struct fuse_conn { /** waitq for blocked connection */ wait_queue_head_t blocked_waitq; - /** RW semaphore for exclusion with fuse_put_super() */ - struct rw_semaphore sbput_sem; - /** The next unique request id */ u64 reqctr; - /** Mount is active */ - unsigned mounted; - /** Connection established, cleared on umount, connection abort and device release */ unsigned connected; @@ -383,12 +373,9 @@ void fuse_file_free(struct fuse_file *ff); void fuse_finish_open(struct inode *inode, struct file *file, struct fuse_file *ff, struct fuse_open_out *outarg); -/** - * Send a RELEASE request - */ -void fuse_send_release(struct fuse_conn *fc, struct fuse_file *ff, - u64 nodeid, struct inode *inode, int flags, int isdir); - +/** */ +struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, + int opcode); /** * Send RELEASE or RELEASEDIR request */ @@ -445,11 +432,6 @@ struct fuse_req *fuse_request_alloc(void); */ void fuse_request_free(struct fuse_req *req); -/** - * Reinitialize a request, the preallocated flag is left unmodified - */ -void fuse_reset_request(struct fuse_req *req); - /** * Reserve a preallocated request */ @@ -476,11 +458,6 @@ void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req); */ void request_send_background(struct fuse_conn *fc, struct fuse_req *req); -/** - * Release inodes and file associated with background request - */ -void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req); - /* Abort all requests */ void fuse_abort_conn(struct fuse_conn *fc); -- cgit v1.2.3 From bafa96541b250a7051e3fbc5de6e8369daf8ffec Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:51 -0700 Subject: [PATCH] fuse: add control filesystem Add a control filesystem to fuse, replacing the attributes currently exported through sysfs. An empty directory '/sys/fs/fuse/connections' is still created in sysfs, and mounting the control filesystem here provides backward compatibility. Advantages of the control filesystem over the previous solution: - allows the object directory and the attributes to be owned by the filesystem owner, hence letting unpriviled users abort the filesystem connection - does not suffer from module unload race [akpm@osdl.org: fix this fs for recent dhowells depredations] [akpm@osdl.org: fix 64-bit printk warnings] Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/fuse.txt | 30 +++-- fs/fuse/Makefile | 2 +- fs/fuse/control.c | 218 +++++++++++++++++++++++++++++++++++++ fs/fuse/dev.c | 2 +- fs/fuse/fuse_i.h | 53 +++++++-- fs/fuse/inode.c | 141 ++++++++---------------- 6 files changed, 331 insertions(+), 115 deletions(-) create mode 100644 fs/fuse/control.c (limited to 'fs/fuse/fuse_i.h') diff --git a/Documentation/filesystems/fuse.txt b/Documentation/filesystems/fuse.txt index e7747774ceb9..324df27704cc 100644 --- a/Documentation/filesystems/fuse.txt +++ b/Documentation/filesystems/fuse.txt @@ -18,6 +18,14 @@ Non-privileged mount (or user mount): user. NOTE: this is not the same as mounts allowed with the "user" option in /etc/fstab, which is not discussed here. +Filesystem connection: + + A connection between the filesystem daemon and the kernel. The + connection exists until either the daemon dies, or the filesystem is + umounted. Note that detaching (or lazy umounting) the filesystem + does _not_ break the connection, in this case it will exist until + the last reference to the filesystem is released. + Mount owner: The user who does the mounting. @@ -86,16 +94,20 @@ Mount options The default is infinite. Note that the size of read requests is limited anyway to 32 pages (which is 128kbyte on i386). -Sysfs -~~~~~ +Control filesystem +~~~~~~~~~~~~~~~~~~ + +There's a control filesystem for FUSE, which can be mounted by: -FUSE sets up the following hierarchy in sysfs: + mount -t fusectl none /sys/fs/fuse/connections - /sys/fs/fuse/connections/N/ +Mounting it under the '/sys/fs/fuse/connections' directory makes it +backwards compatible with earlier versions. -where N is an increasing number allocated to each new connection. +Under the fuse control filesystem each connection has a directory +named by a unique number. -For each connection the following attributes are defined: +For each connection the following files exist within this directory: 'waiting' @@ -110,7 +122,7 @@ For each connection the following attributes are defined: connection. This means that all waiting requests will be aborted an error returned for all aborted and new requests. -Only a privileged user may read or write these attributes. +Only the owner of the mount may read or write these files. Aborting a filesystem connection ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -139,8 +151,8 @@ the filesystem. There are several ways to do this: - Use forced umount (umount -f). Works in all cases but only if filesystem is still attached (it hasn't been lazy unmounted) - - Abort filesystem through the sysfs interface. Most powerful - method, always works. + - Abort filesystem through the FUSE control filesystem. Most + powerful method, always works. How do non-privileged mounts work? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/fs/fuse/Makefile b/fs/fuse/Makefile index c3e1f760cac9..72437065f6ad 100644 --- a/fs/fuse/Makefile +++ b/fs/fuse/Makefile @@ -4,4 +4,4 @@ obj-$(CONFIG_FUSE_FS) += fuse.o -fuse-objs := dev.o dir.o file.o inode.o +fuse-objs := dev.o dir.o file.o inode.o control.o diff --git a/fs/fuse/control.c b/fs/fuse/control.c new file mode 100644 index 000000000000..a3bce3a77253 --- /dev/null +++ b/fs/fuse/control.c @@ -0,0 +1,218 @@ +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2006 Miklos Szeredi + + This program can be distributed under the terms of the GNU GPL. + See the file COPYING. +*/ + +#include "fuse_i.h" + +#include +#include + +#define FUSE_CTL_SUPER_MAGIC 0x65735543 + +/* + * This is non-NULL when the single instance of the control filesystem + * exists. Protected by fuse_mutex + */ +static struct super_block *fuse_control_sb; + +static struct fuse_conn *fuse_ctl_file_conn_get(struct file *file) +{ + struct fuse_conn *fc; + mutex_lock(&fuse_mutex); + fc = file->f_dentry->d_inode->u.generic_ip; + if (fc) + fc = fuse_conn_get(fc); + mutex_unlock(&fuse_mutex); + return fc; +} + +static ssize_t fuse_conn_abort_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct fuse_conn *fc = fuse_ctl_file_conn_get(file); + if (fc) { + fuse_abort_conn(fc); + fuse_conn_put(fc); + } + return count; +} + +static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf, + size_t len, loff_t *ppos) +{ + char tmp[32]; + size_t size; + + if (!*ppos) { + struct fuse_conn *fc = fuse_ctl_file_conn_get(file); + if (!fc) + return 0; + + file->private_data=(void *)(long)atomic_read(&fc->num_waiting); + fuse_conn_put(fc); + } + size = sprintf(tmp, "%ld\n", (long)file->private_data); + return simple_read_from_buffer(buf, len, ppos, tmp, size); +} + +static const struct file_operations fuse_ctl_abort_ops = { + .open = nonseekable_open, + .write = fuse_conn_abort_write, +}; + +static const struct file_operations fuse_ctl_waiting_ops = { + .open = nonseekable_open, + .read = fuse_conn_waiting_read, +}; + +static struct dentry *fuse_ctl_add_dentry(struct dentry *parent, + struct fuse_conn *fc, + const char *name, + int mode, int nlink, + struct inode_operations *iop, + const struct file_operations *fop) +{ + struct dentry *dentry; + struct inode *inode; + + BUG_ON(fc->ctl_ndents >= FUSE_CTL_NUM_DENTRIES); + dentry = d_alloc_name(parent, name); + if (!dentry) + return NULL; + + fc->ctl_dentry[fc->ctl_ndents++] = dentry; + inode = new_inode(fuse_control_sb); + if (!inode) + return NULL; + + inode->i_mode = mode; + inode->i_uid = fc->user_id; + inode->i_gid = fc->group_id; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + /* setting ->i_op to NULL is not allowed */ + if (iop) + inode->i_op = iop; + inode->i_fop = fop; + inode->i_nlink = nlink; + inode->u.generic_ip = fc; + d_add(dentry, inode); + return dentry; +} + +/* + * Add a connection to the control filesystem (if it exists). Caller + * must host fuse_mutex + */ +int fuse_ctl_add_conn(struct fuse_conn *fc) +{ + struct dentry *parent; + char name[32]; + + if (!fuse_control_sb) + return 0; + + parent = fuse_control_sb->s_root; + parent->d_inode->i_nlink++; + sprintf(name, "%llu", (unsigned long long) fc->id); + parent = fuse_ctl_add_dentry(parent, fc, name, S_IFDIR | 0500, 2, + &simple_dir_inode_operations, + &simple_dir_operations); + if (!parent) + goto err; + + if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG | 0400, 1, + NULL, &fuse_ctl_waiting_ops) || + !fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG | 0200, 1, + NULL, &fuse_ctl_abort_ops)) + goto err; + + return 0; + + err: + fuse_ctl_remove_conn(fc); + return -ENOMEM; +} + +/* + * Remove a connection from the control filesystem (if it exists). + * Caller must host fuse_mutex + */ +void fuse_ctl_remove_conn(struct fuse_conn *fc) +{ + int i; + + if (!fuse_control_sb) + return; + + for (i = fc->ctl_ndents - 1; i >= 0; i--) { + struct dentry *dentry = fc->ctl_dentry[i]; + dentry->d_inode->u.generic_ip = NULL; + d_drop(dentry); + dput(dentry); + } + fuse_control_sb->s_root->d_inode->i_nlink--; +} + +static int fuse_ctl_fill_super(struct super_block *sb, void *data, int silent) +{ + struct tree_descr empty_descr = {""}; + struct fuse_conn *fc; + int err; + + err = simple_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr); + if (err) + return err; + + mutex_lock(&fuse_mutex); + BUG_ON(fuse_control_sb); + fuse_control_sb = sb; + list_for_each_entry(fc, &fuse_conn_list, entry) { + err = fuse_ctl_add_conn(fc); + if (err) { + fuse_control_sb = NULL; + mutex_unlock(&fuse_mutex); + return err; + } + } + mutex_unlock(&fuse_mutex); + + return 0; +} + +static int fuse_ctl_get_sb(struct file_system_type *fs_type, int flags, + const char *dev_name, void *raw_data, + struct vfsmount *mnt) +{ + return get_sb_single(fs_type, flags, raw_data, + fuse_ctl_fill_super, mnt); +} + +static void fuse_ctl_kill_sb(struct super_block *sb) +{ + mutex_lock(&fuse_mutex); + fuse_control_sb = NULL; + mutex_unlock(&fuse_mutex); + + kill_litter_super(sb); +} + +static struct file_system_type fuse_ctl_fs_type = { + .owner = THIS_MODULE, + .name = "fusectl", + .get_sb = fuse_ctl_get_sb, + .kill_sb = fuse_ctl_kill_sb, +}; + +int __init fuse_ctl_init(void) +{ + return register_filesystem(&fuse_ctl_fs_type); +} + +void fuse_ctl_cleanup(void) +{ + unregister_filesystem(&fuse_ctl_fs_type); +} diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index fec4779e2b55..fe3adf589174 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -833,7 +833,7 @@ static int fuse_dev_release(struct inode *inode, struct file *file) end_requests(fc, &fc->processing); spin_unlock(&fc->lock); fasync_helper(-1, file, 0, &fc->fasync); - kobject_put(&fc->kobj); + fuse_conn_put(fc); } return 0; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 25f8581a770c..ac12b01f4446 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -14,6 +14,7 @@ #include #include #include +#include /** Max number of pages that can be used in a single read request */ #define FUSE_MAX_PAGES_PER_REQ 32 @@ -24,6 +25,9 @@ /** It could be as large as PATH_MAX, but would that have any uses? */ #define FUSE_NAME_MAX 1024 +/** Number of dentries for each connection in the control filesystem */ +#define FUSE_CTL_NUM_DENTRIES 3 + /** If the FUSE_DEFAULT_PERMISSIONS flag is given, the filesystem module will check permissions based on the file mode. Otherwise no permission checking is done in the kernel */ @@ -33,6 +37,11 @@ doing the mount will be allowed to access the filesystem */ #define FUSE_ALLOW_OTHER (1 << 1) +/** List of active connections */ +extern struct list_head fuse_conn_list; + +/** Global mutex protecting fuse_conn_list and the control filesystem */ +extern struct mutex fuse_mutex; /** FUSE inode */ struct fuse_inode { @@ -216,6 +225,9 @@ struct fuse_conn { /** Lock protecting accessess to members of this structure */ spinlock_t lock; + /** Refcount */ + atomic_t count; + /** The user id for this mount */ uid_t user_id; @@ -310,8 +322,17 @@ struct fuse_conn { /** Backing dev info */ struct backing_dev_info bdi; - /** kobject */ - struct kobject kobj; + /** Entry on the fuse_conn_list */ + struct list_head entry; + + /** Unique ID */ + u64 id; + + /** Dentries in the control filesystem */ + struct dentry *ctl_dentry[FUSE_CTL_NUM_DENTRIES]; + + /** number of dentries used in the above array */ + int ctl_ndents; /** O_ASYNC requests */ struct fasync_struct *fasync; @@ -327,11 +348,6 @@ static inline struct fuse_conn *get_fuse_conn(struct inode *inode) return get_fuse_conn_super(inode->i_sb); } -static inline struct fuse_conn *get_fuse_conn_kobj(struct kobject *obj) -{ - return container_of(obj, struct fuse_conn, kobj); -} - static inline struct fuse_inode *get_fuse_inode(struct inode *inode) { return container_of(inode, struct fuse_inode, inode); @@ -422,6 +438,9 @@ int fuse_dev_init(void); */ void fuse_dev_cleanup(void); +int fuse_ctl_init(void); +void fuse_ctl_cleanup(void); + /** * Allocate a request */ @@ -470,3 +489,23 @@ int fuse_do_getattr(struct inode *inode); * Invalidate inode attributes */ void fuse_invalidate_attr(struct inode *inode); + +/** + * Acquire reference to fuse_conn + */ +struct fuse_conn *fuse_conn_get(struct fuse_conn *fc); + +/** + * Release reference to fuse_conn + */ +void fuse_conn_put(struct fuse_conn *fc); + +/** + * Add connection to control filesystem + */ +int fuse_ctl_add_conn(struct fuse_conn *fc); + +/** + * Remove connection from control filesystem + */ +void fuse_ctl_remove_conn(struct fuse_conn *fc); diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 0225729977c4..13a7e8ab7a78 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -22,13 +22,8 @@ MODULE_DESCRIPTION("Filesystem in Userspace"); MODULE_LICENSE("GPL"); static kmem_cache_t *fuse_inode_cachep; -static struct subsystem connections_subsys; - -struct fuse_conn_attr { - struct attribute attr; - ssize_t (*show)(struct fuse_conn *, char *); - ssize_t (*store)(struct fuse_conn *, const char *, size_t); -}; +struct list_head fuse_conn_list; +DEFINE_MUTEX(fuse_mutex); #define FUSE_SUPER_MAGIC 0x65735546 @@ -211,8 +206,11 @@ static void fuse_put_super(struct super_block *sb) kill_fasync(&fc->fasync, SIGIO, POLL_IN); wake_up_all(&fc->waitq); wake_up_all(&fc->blocked_waitq); - kobject_del(&fc->kobj); - kobject_put(&fc->kobj); + mutex_lock(&fuse_mutex); + list_del(&fc->entry); + fuse_ctl_remove_conn(fc); + mutex_unlock(&fuse_mutex); + fuse_conn_put(fc); } static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) @@ -362,11 +360,6 @@ static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) return 0; } -static void fuse_conn_release(struct kobject *kobj) -{ - kfree(get_fuse_conn_kobj(kobj)); -} - static struct fuse_conn *new_conn(void) { struct fuse_conn *fc; @@ -374,13 +367,12 @@ static struct fuse_conn *new_conn(void) fc = kzalloc(sizeof(*fc), GFP_KERNEL); if (fc) { spin_lock_init(&fc->lock); + atomic_set(&fc->count, 1); init_waitqueue_head(&fc->waitq); init_waitqueue_head(&fc->blocked_waitq); INIT_LIST_HEAD(&fc->pending); INIT_LIST_HEAD(&fc->processing); INIT_LIST_HEAD(&fc->io); - kobj_set_kset_s(fc, connections_subsys); - kobject_init(&fc->kobj); atomic_set(&fc->num_waiting, 0); fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; fc->bdi.unplug_io_fn = default_unplug_io_fn; @@ -390,6 +382,18 @@ static struct fuse_conn *new_conn(void) return fc; } +void fuse_conn_put(struct fuse_conn *fc) +{ + if (atomic_dec_and_test(&fc->count)) + kfree(fc); +} + +struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) +{ + atomic_inc(&fc->count); + return fc; +} + static struct inode *get_root_inode(struct super_block *sb, unsigned mode) { struct fuse_attr attr; @@ -459,10 +463,9 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) request_send_background(fc, req); } -static unsigned long long conn_id(void) +static u64 conn_id(void) { - /* BKL is held for ->get_sb() */ - static unsigned long long ctr = 1; + static u64 ctr = 1; return ctr++; } @@ -519,24 +522,21 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) if (!init_req) goto err_put_root; - err = kobject_set_name(&fc->kobj, "%llu", conn_id()); - if (err) - goto err_free_req; - - err = kobject_add(&fc->kobj); - if (err) - goto err_free_req; - - /* Setting file->private_data can't race with other mount() - instances, since BKL is held for ->get_sb() */ + mutex_lock(&fuse_mutex); err = -EINVAL; if (file->private_data) - goto err_kobject_del; + goto err_unlock; + fc->id = conn_id(); + err = fuse_ctl_add_conn(fc); + if (err) + goto err_unlock; + + list_add_tail(&fc->entry, &fuse_conn_list); sb->s_root = root_dentry; fc->connected = 1; - kobject_get(&fc->kobj); - file->private_data = fc; + file->private_data = fuse_conn_get(fc); + mutex_unlock(&fuse_mutex); /* * atomic_dec_and_test() in fput() provides the necessary * memory barrier for file->private_data to be visible on all @@ -548,15 +548,14 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) return 0; - err_kobject_del: - kobject_del(&fc->kobj); - err_free_req: + err_unlock: + mutex_unlock(&fuse_mutex); fuse_request_free(init_req); err_put_root: dput(root_dentry); err: fput(file); - kobject_put(&fc->kobj); + fuse_conn_put(fc); return err; } @@ -574,68 +573,8 @@ static struct file_system_type fuse_fs_type = { .kill_sb = kill_anon_super, }; -static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page) -{ - return sprintf(page, "%i\n", atomic_read(&fc->num_waiting)); -} - -static ssize_t fuse_conn_abort_store(struct fuse_conn *fc, const char *page, - size_t count) -{ - fuse_abort_conn(fc); - return count; -} - -static struct fuse_conn_attr fuse_conn_waiting = - __ATTR(waiting, 0400, fuse_conn_waiting_show, NULL); -static struct fuse_conn_attr fuse_conn_abort = - __ATTR(abort, 0600, NULL, fuse_conn_abort_store); - -static struct attribute *fuse_conn_attrs[] = { - &fuse_conn_waiting.attr, - &fuse_conn_abort.attr, - NULL, -}; - -static ssize_t fuse_conn_attr_show(struct kobject *kobj, - struct attribute *attr, - char *page) -{ - struct fuse_conn_attr *fca = - container_of(attr, struct fuse_conn_attr, attr); - - if (fca->show) - return fca->show(get_fuse_conn_kobj(kobj), page); - else - return -EACCES; -} - -static ssize_t fuse_conn_attr_store(struct kobject *kobj, - struct attribute *attr, - const char *page, size_t count) -{ - struct fuse_conn_attr *fca = - container_of(attr, struct fuse_conn_attr, attr); - - if (fca->store) - return fca->store(get_fuse_conn_kobj(kobj), page, count); - else - return -EACCES; -} - -static struct sysfs_ops fuse_conn_sysfs_ops = { - .show = &fuse_conn_attr_show, - .store = &fuse_conn_attr_store, -}; - -static struct kobj_type ktype_fuse_conn = { - .release = fuse_conn_release, - .sysfs_ops = &fuse_conn_sysfs_ops, - .default_attrs = fuse_conn_attrs, -}; - static decl_subsys(fuse, NULL, NULL); -static decl_subsys(connections, &ktype_fuse_conn, NULL); +static decl_subsys(connections, NULL, NULL); static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) @@ -709,6 +648,7 @@ static int __init fuse_init(void) printk("fuse init (API version %i.%i)\n", FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); + INIT_LIST_HEAD(&fuse_conn_list); res = fuse_fs_init(); if (res) goto err; @@ -721,8 +661,14 @@ static int __init fuse_init(void) if (res) goto err_dev_cleanup; + res = fuse_ctl_init(); + if (res) + goto err_sysfs_cleanup; + return 0; + err_sysfs_cleanup: + fuse_sysfs_cleanup(); err_dev_cleanup: fuse_dev_cleanup(); err_fs_cleanup: @@ -735,6 +681,7 @@ static void __exit fuse_exit(void) { printk(KERN_DEBUG "fuse exit\n"); + fuse_ctl_cleanup(); fuse_sysfs_cleanup(); fuse_fs_cleanup(); fuse_dev_cleanup(); -- cgit v1.2.3 From 7142125937e1482ad3ae4366594c6586153dfc86 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:52 -0700 Subject: [PATCH] fuse: add POSIX file locking support This patch adds POSIX file locking support to the fuse interface. This implementation doesn't keep any locking state in kernel. Unlocking on close() is handled by the FLUSH message, which now contains the lock owner id. Mandatory locking is not supported. The filesystem may enfoce mandatory locking in userspace if needed. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/file.c | 132 +++++++++++++++++++++++++++++++++++++++++++++++++++ fs/fuse/fuse_i.h | 4 ++ fs/fuse/inode.c | 20 +++++++- include/linux/fuse.h | 26 +++++++++- 4 files changed, 178 insertions(+), 4 deletions(-) (limited to 'fs/fuse/fuse_i.h') diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 1d59af306b28..d9a8289297c0 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -160,6 +160,18 @@ static int fuse_release(struct inode *inode, struct file *file) return fuse_release_common(inode, file, 0); } +/* + * It would be nice to scramble the ID space, so that the value of the + * files_struct pointer is not exposed to userspace. Symmetric crypto + * functions are overkill, since the inverse function doesn't need to + * be implemented (though it does have to exist). Is there something + * simpler? + */ +static inline u64 fuse_lock_owner_id(fl_owner_t id) +{ + return (unsigned long) id; +} + static int fuse_flush(struct file *file, fl_owner_t id) { struct inode *inode = file->f_dentry->d_inode; @@ -181,11 +193,13 @@ static int fuse_flush(struct file *file, fl_owner_t id) memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; + inarg.lock_owner = fuse_lock_owner_id(id); req->in.h.opcode = FUSE_FLUSH; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; req->in.args[0].size = sizeof(inarg); req->in.args[0].value = &inarg; + req->force = 1; request_send(fc, req); err = req->out.h.error; fuse_put_request(fc, req); @@ -604,6 +618,122 @@ static int fuse_set_page_dirty(struct page *page) return 0; } +static int convert_fuse_file_lock(const struct fuse_file_lock *ffl, + struct file_lock *fl) +{ + switch (ffl->type) { + case F_UNLCK: + break; + + case F_RDLCK: + case F_WRLCK: + if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX || + ffl->end < ffl->start) + return -EIO; + + fl->fl_start = ffl->start; + fl->fl_end = ffl->end; + fl->fl_pid = ffl->pid; + break; + + default: + return -EIO; + } + fl->fl_type = ffl->type; + return 0; +} + +static void fuse_lk_fill(struct fuse_req *req, struct file *file, + const struct file_lock *fl, int opcode, pid_t pid) +{ + struct inode *inode = file->f_dentry->d_inode; + struct fuse_file *ff = file->private_data; + struct fuse_lk_in *arg = &req->misc.lk_in; + + arg->fh = ff->fh; + arg->owner = fuse_lock_owner_id(fl->fl_owner); + arg->lk.start = fl->fl_start; + arg->lk.end = fl->fl_end; + arg->lk.type = fl->fl_type; + arg->lk.pid = pid; + req->in.h.opcode = opcode; + req->in.h.nodeid = get_node_id(inode); + req->in.numargs = 1; + req->in.args[0].size = sizeof(*arg); + req->in.args[0].value = arg; +} + +static int fuse_getlk(struct file *file, struct file_lock *fl) +{ + struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req; + struct fuse_lk_out outarg; + int err; + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return PTR_ERR(req); + + fuse_lk_fill(req, file, fl, FUSE_GETLK, 0); + req->out.numargs = 1; + req->out.args[0].size = sizeof(outarg); + req->out.args[0].value = &outarg; + request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + if (!err) + err = convert_fuse_file_lock(&outarg.lk, fl); + + return err; +} + +static int fuse_setlk(struct file *file, struct file_lock *fl) +{ + struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_req *req; + int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK; + pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0; + int err; + + /* Unlock on close is handled by the flush method */ + if (fl->fl_flags & FL_CLOSE) + return 0; + + req = fuse_get_req(fc); + if (IS_ERR(req)) + return PTR_ERR(req); + + fuse_lk_fill(req, file, fl, opcode, pid); + request_send(fc, req); + err = req->out.h.error; + fuse_put_request(fc, req); + return err; +} + +static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) +{ + struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + int err; + + if (cmd == F_GETLK) { + if (fc->no_lock) { + if (!posix_test_lock(file, fl, fl)) + fl->fl_type = F_UNLCK; + err = 0; + } else + err = fuse_getlk(file, fl); + } else { + if (fc->no_lock) + err = posix_lock_file_wait(file, fl); + else + err = fuse_setlk(file, fl); + } + return err; +} + static const struct file_operations fuse_file_operations = { .llseek = generic_file_llseek, .read = generic_file_read, @@ -613,6 +743,7 @@ static const struct file_operations fuse_file_operations = { .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, + .lock = fuse_file_lock, .sendfile = generic_file_sendfile, }; @@ -624,6 +755,7 @@ static const struct file_operations fuse_direct_io_file_operations = { .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, + .lock = fuse_file_lock, /* no mmap and sendfile */ }; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index ac12b01f4446..eb3166625ca9 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -190,6 +190,7 @@ struct fuse_req { struct fuse_init_in init_in; struct fuse_init_out init_out; struct fuse_read_in read_in; + struct fuse_lk_in lk_in; } misc; /** page vector */ @@ -307,6 +308,9 @@ struct fuse_conn { /** Is removexattr not implemented by fs? */ unsigned no_removexattr : 1; + /** Are file locking primitives not implemented by fs? */ + unsigned no_lock : 1; + /** Is access not implemented by fs? */ unsigned no_access : 1; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 13a7e8ab7a78..412892905838 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -98,6 +98,14 @@ static void fuse_clear_inode(struct inode *inode) } } +static int fuse_remount_fs(struct super_block *sb, int *flags, char *data) +{ + if (*flags & MS_MANDLOCK) + return -EINVAL; + + return 0; +} + void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr) { if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size) @@ -409,6 +417,7 @@ static struct super_operations fuse_super_operations = { .destroy_inode = fuse_destroy_inode, .read_inode = fuse_read_inode, .clear_inode = fuse_clear_inode, + .remount_fs = fuse_remount_fs, .put_super = fuse_put_super, .umount_begin = fuse_umount_begin, .statfs = fuse_statfs, @@ -428,8 +437,12 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) ra_pages = arg->max_readahead / PAGE_CACHE_SIZE; if (arg->flags & FUSE_ASYNC_READ) fc->async_read = 1; - } else + if (!(arg->flags & FUSE_POSIX_LOCKS)) + fc->no_lock = 1; + } else { ra_pages = fc->max_read / PAGE_CACHE_SIZE; + fc->no_lock = 1; + } fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages); fc->minor = arg->minor; @@ -447,7 +460,7 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req) arg->major = FUSE_KERNEL_VERSION; arg->minor = FUSE_KERNEL_MINOR_VERSION; arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE; - arg->flags |= FUSE_ASYNC_READ; + arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS; req->in.h.opcode = FUSE_INIT; req->in.numargs = 1; req->in.args[0].size = sizeof(*arg); @@ -479,6 +492,9 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) struct fuse_req *init_req; int err; + if (sb->s_flags & MS_MANDLOCK) + return -EINVAL; + if (!parse_fuse_opt((char *) data, &d)) return -EINVAL; diff --git a/include/linux/fuse.h b/include/linux/fuse.h index 8e4319614bef..e7a76ec0f05c 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -1,6 +1,6 @@ /* FUSE: Filesystem in Userspace - Copyright (C) 2001-2005 Miklos Szeredi + Copyright (C) 2001-2006 Miklos Szeredi This program can be distributed under the terms of the GNU GPL. See the file COPYING. @@ -15,7 +15,7 @@ #define FUSE_KERNEL_VERSION 7 /** Minor version number of this interface */ -#define FUSE_KERNEL_MINOR_VERSION 6 +#define FUSE_KERNEL_MINOR_VERSION 7 /** The node ID of the root inode */ #define FUSE_ROOT_ID 1 @@ -59,6 +59,13 @@ struct fuse_kstatfs { __u32 spare[6]; }; +struct fuse_file_lock { + __u64 start; + __u64 end; + __u32 type; + __u32 pid; /* tgid */ +}; + /** * Bitmasks for fuse_setattr_in.valid */ @@ -83,6 +90,7 @@ struct fuse_kstatfs { * INIT request/reply flags */ #define FUSE_ASYNC_READ (1 << 0) +#define FUSE_POSIX_LOCKS (1 << 1) enum fuse_opcode { FUSE_LOOKUP = 1, @@ -113,6 +121,9 @@ enum fuse_opcode { FUSE_READDIR = 28, FUSE_RELEASEDIR = 29, FUSE_FSYNCDIR = 30, + FUSE_GETLK = 31, + FUSE_SETLK = 32, + FUSE_SETLKW = 33, FUSE_ACCESS = 34, FUSE_CREATE = 35 }; @@ -200,6 +211,7 @@ struct fuse_flush_in { __u64 fh; __u32 flush_flags; __u32 padding; + __u64 lock_owner; }; struct fuse_read_in { @@ -248,6 +260,16 @@ struct fuse_getxattr_out { __u32 padding; }; +struct fuse_lk_in { + __u64 fh; + __u64 owner; + struct fuse_file_lock lk; +}; + +struct fuse_lk_out { + struct fuse_file_lock lk; +}; + struct fuse_access_in { __u32 mask; __u32 padding; -- cgit v1.2.3 From 33649c91a3df57c1090a657637d44b896de367e7 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:52 -0700 Subject: [PATCH] fuse: ensure FLUSH reaches userspace All POSIX locks owned by the current task are removed on close(). If the FLUSH request resulting initiated by close() fails to reach userspace, there might be locks remaining, which cannot be removed. The only reason it could fail, is if allocating the request fails. In this case use the request reserved for RELEASE, or if that is currently used by another FLUSH, wait for it to become available. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/dev.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++--- fs/fuse/file.c | 13 ++++----- fs/fuse/fuse_i.h | 12 ++++++-- 3 files changed, 99 insertions(+), 14 deletions(-) (limited to 'fs/fuse/fuse_i.h') diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index fe3adf589174..ae26f37e53a1 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -76,6 +76,13 @@ static void __fuse_put_request(struct fuse_req *req) atomic_dec(&req->count); } +static void fuse_req_init_context(struct fuse_req *req) +{ + req->in.h.uid = current->fsuid; + req->in.h.gid = current->fsgid; + req->in.h.pid = current->pid; +} + struct fuse_req *fuse_get_req(struct fuse_conn *fc) { struct fuse_req *req; @@ -100,9 +107,7 @@ struct fuse_req *fuse_get_req(struct fuse_conn *fc) if (!req) goto out; - req->in.h.uid = current->fsuid; - req->in.h.gid = current->fsgid; - req->in.h.pid = current->pid; + fuse_req_init_context(req); req->waiting = 1; return req; @@ -111,12 +116,87 @@ struct fuse_req *fuse_get_req(struct fuse_conn *fc) return ERR_PTR(err); } +/* + * Return request in fuse_file->reserved_req. However that may + * currently be in use. If that is the case, wait for it to become + * available. + */ +static struct fuse_req *get_reserved_req(struct fuse_conn *fc, + struct file *file) +{ + struct fuse_req *req = NULL; + struct fuse_file *ff = file->private_data; + + do { + wait_event(fc->blocked_waitq, ff->reserved_req); + spin_lock(&fc->lock); + if (ff->reserved_req) { + req = ff->reserved_req; + ff->reserved_req = NULL; + get_file(file); + req->stolen_file = file; + } + spin_unlock(&fc->lock); + } while (!req); + + return req; +} + +/* + * Put stolen request back into fuse_file->reserved_req + */ +static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req) +{ + struct file *file = req->stolen_file; + struct fuse_file *ff = file->private_data; + + spin_lock(&fc->lock); + fuse_request_init(req); + BUG_ON(ff->reserved_req); + ff->reserved_req = req; + wake_up(&fc->blocked_waitq); + spin_unlock(&fc->lock); + fput(file); +} + +/* + * Gets a requests for a file operation, always succeeds + * + * This is used for sending the FLUSH request, which must get to + * userspace, due to POSIX locks which may need to be unlocked. + * + * If allocation fails due to OOM, use the reserved request in + * fuse_file. + * + * This is very unlikely to deadlock accidentally, since the + * filesystem should not have it's own file open. If deadlock is + * intentional, it can still be broken by "aborting" the filesystem. + */ +struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file) +{ + struct fuse_req *req; + + atomic_inc(&fc->num_waiting); + wait_event(fc->blocked_waitq, !fc->blocked); + req = fuse_request_alloc(); + if (!req) + req = get_reserved_req(fc, file); + + fuse_req_init_context(req); + req->waiting = 1; + return req; +} + void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) { if (atomic_dec_and_test(&req->count)) { if (req->waiting) atomic_dec(&fc->num_waiting); - fuse_request_free(req); + + if (req->stolen_file) + put_reserved_req(fc, req); + else + fuse_request_free(req); } } diff --git a/fs/fuse/file.c b/fs/fuse/file.c index d9a8289297c0..ce759414cff9 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -48,8 +48,8 @@ struct fuse_file *fuse_file_alloc(void) struct fuse_file *ff; ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL); if (ff) { - ff->release_req = fuse_request_alloc(); - if (!ff->release_req) { + ff->reserved_req = fuse_request_alloc(); + if (!ff->reserved_req) { kfree(ff); ff = NULL; } @@ -59,7 +59,7 @@ struct fuse_file *fuse_file_alloc(void) void fuse_file_free(struct fuse_file *ff) { - fuse_request_free(ff->release_req); + fuse_request_free(ff->reserved_req); kfree(ff); } @@ -115,7 +115,7 @@ int fuse_open_common(struct inode *inode, struct file *file, int isdir) struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode) { - struct fuse_req *req = ff->release_req; + struct fuse_req *req = ff->reserved_req; struct fuse_release_in *inarg = &req->misc.release_in; inarg->fh = ff->fh; @@ -187,10 +187,7 @@ static int fuse_flush(struct file *file, fl_owner_t id) if (fc->no_flush) return 0; - req = fuse_get_req(fc); - if (IS_ERR(req)) - return PTR_ERR(req); - + req = fuse_get_req_nofail(fc, file); memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; inarg.lock_owner = fuse_lock_owner_id(id); diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index eb3166625ca9..f7c74516f3a6 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -65,7 +65,7 @@ struct fuse_inode { /** FUSE specific file data */ struct fuse_file { /** Request reserved for flush and release */ - struct fuse_req *release_req; + struct fuse_req *reserved_req; /** File handle used by userspace */ u64 fh; @@ -213,6 +213,9 @@ struct fuse_req { /** Request completion callback */ void (*end)(struct fuse_conn *, struct fuse_req *); + + /** Request is stolen from fuse_file->reserved_req */ + struct file *stolen_file; }; /** @@ -456,10 +459,15 @@ struct fuse_req *fuse_request_alloc(void); void fuse_request_free(struct fuse_req *req); /** - * Reserve a preallocated request + * Get a request, may fail with -ENOMEM */ struct fuse_req *fuse_get_req(struct fuse_conn *fc); +/** + * Gets a requests for a file operation, always succeeds + */ +struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file); + /** * Decrement reference count of a request. If count goes to zero free * the request. -- cgit v1.2.3 From f9a2842e5612b93fa20a624a8baa6c2a7ecea504 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:53 -0700 Subject: [PATCH] fuse: rename the interrupted flag Rename the 'interrupted' flag to 'aborted', since it indicates exactly that, and next patch will introduce an 'interrupted' flag for a Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/dev.c | 39 +++++++++++++++++++-------------------- fs/fuse/fuse_i.h | 4 ++-- 2 files changed, 21 insertions(+), 22 deletions(-) (limited to 'fs/fuse/fuse_i.h') diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index ae26f37e53a1..6b5f74cb7b54 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -202,7 +202,7 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) /* * This function is called when a request is finished. Either a reply - * has arrived or it was interrupted (and not yet sent) or some error + * has arrived or it was aborted (and not yet sent) or some error * occurred during communication with userspace, or the device file * was closed. The requester thread is woken up (if still waiting), * the 'end' callback is called if given, else the reference to the @@ -250,12 +250,12 @@ static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) restore_sigs(&oldset); } spin_lock(&fc->lock); - if (req->state == FUSE_REQ_FINISHED && !req->interrupted) + if (req->state == FUSE_REQ_FINISHED && !req->aborted) return; - if (!req->interrupted) { + if (!req->aborted) { req->out.h.error = -EINTR; - req->interrupted = 1; + req->aborted = 1; } if (req->locked) { /* This is uninterruptible sleep, because data is @@ -361,14 +361,14 @@ void request_send_background(struct fuse_conn *fc, struct fuse_req *req) /* * Lock the request. Up to the next unlock_request() there mustn't be * anything that could cause a page-fault. If the request was already - * interrupted bail out. + * aborted bail out. */ static int lock_request(struct fuse_conn *fc, struct fuse_req *req) { int err = 0; if (req) { spin_lock(&fc->lock); - if (req->interrupted) + if (req->aborted) err = -ENOENT; else req->locked = 1; @@ -378,7 +378,7 @@ static int lock_request(struct fuse_conn *fc, struct fuse_req *req) } /* - * Unlock request. If it was interrupted during being locked, the + * Unlock request. If it was aborted during being locked, the * requester thread is currently waiting for it to be unlocked, so * wake it up. */ @@ -387,7 +387,7 @@ static void unlock_request(struct fuse_conn *fc, struct fuse_req *req) if (req) { spin_lock(&fc->lock); req->locked = 0; - if (req->interrupted) + if (req->aborted) wake_up(&req->waitq); spin_unlock(&fc->lock); } @@ -589,8 +589,8 @@ static void request_wait(struct fuse_conn *fc) * Read a single request into the userspace filesystem's buffer. This * function waits until a request is available, then removes it from * the pending list and copies request data to userspace buffer. If - * no reply is needed (FORGET) or request has been interrupted or - * there was an error during the copying then it's finished by calling + * no reply is needed (FORGET) or request has been aborted or there + * was an error during the copying then it's finished by calling * request_end(). Otherwise add it to the processing list, and set * the 'sent' flag. */ @@ -645,10 +645,10 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov, fuse_copy_finish(&cs); spin_lock(&fc->lock); req->locked = 0; - if (!err && req->interrupted) + if (!err && req->aborted) err = -ENOENT; if (err) { - if (!req->interrupted) + if (!req->aborted) req->out.h.error = -EIO; request_end(fc, req); return err; @@ -754,7 +754,7 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov, if (!req) goto err_unlock; - if (req->interrupted) { + if (req->aborted) { spin_unlock(&fc->lock); fuse_copy_finish(&cs); spin_lock(&fc->lock); @@ -773,9 +773,9 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov, spin_lock(&fc->lock); req->locked = 0; if (!err) { - if (req->interrupted) + if (req->aborted) err = -ENOENT; - } else if (!req->interrupted) + } else if (!req->aborted) req->out.h.error = -EIO; request_end(fc, req); @@ -835,7 +835,7 @@ static void end_requests(struct fuse_conn *fc, struct list_head *head) /* * Abort requests under I/O * - * The requests are set to interrupted and finished, and the request + * The requests are set to aborted and finished, and the request * waiter is woken up. This will make request_wait_answer() wait * until the request is unlocked and then return. * @@ -850,7 +850,7 @@ static void end_io_requests(struct fuse_conn *fc) list_entry(fc->io.next, struct fuse_req, list); void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; - req->interrupted = 1; + req->aborted = 1; req->out.h.error = -ECONNABORTED; req->state = FUSE_REQ_FINISHED; list_del_init(&req->list); @@ -883,9 +883,8 @@ static void end_io_requests(struct fuse_conn *fc) * onto the pending list is prevented by req->connected being false. * * Progression of requests under I/O to the processing list is - * prevented by the req->interrupted flag being true for these - * requests. For this reason requests on the io list must be aborted - * first. + * prevented by the req->aborted flag being true for these requests. + * For this reason requests on the io list must be aborted first. */ void fuse_abort_conn(struct fuse_conn *fc) { diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index f7c74516f3a6..fd65e75e1622 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -159,8 +159,8 @@ struct fuse_req { /** Force sending of the request even if interrupted */ unsigned force:1; - /** The request was interrupted */ - unsigned interrupted:1; + /** The request was aborted */ + unsigned aborted:1; /** Request is sent in the background */ unsigned background:1; -- cgit v1.2.3 From a4d27e75ffb7b8ecb7eed0c7db0df975525f3fd7 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:54 -0700 Subject: [PATCH] fuse: add request interruption Add synchronous request interruption. This is needed for file locking operations which have to be interruptible. However filesystem may implement interruptibility of other operations (e.g. like NFS 'intr' mount option). Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/fuse.txt | 48 ++++++++++- fs/fuse/dev.c | 162 ++++++++++++++++++++++++++++++------- fs/fuse/file.c | 3 + fs/fuse/fuse_i.h | 16 ++++ fs/fuse/inode.c | 1 + include/linux/fuse.h | 7 +- 6 files changed, 205 insertions(+), 32 deletions(-) (limited to 'fs/fuse/fuse_i.h') diff --git a/Documentation/filesystems/fuse.txt b/Documentation/filesystems/fuse.txt index 324df27704cc..a584f05403a4 100644 --- a/Documentation/filesystems/fuse.txt +++ b/Documentation/filesystems/fuse.txt @@ -124,6 +124,46 @@ For each connection the following files exist within this directory: Only the owner of the mount may read or write these files. +Interrupting filesystem operations +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +If a process issuing a FUSE filesystem request is interrupted, the +following will happen: + + 1) If the request is not yet sent to userspace AND the signal is + fatal (SIGKILL or unhandled fatal signal), then the request is + dequeued and returns immediately. + + 2) If the request is not yet sent to userspace AND the signal is not + fatal, then an 'interrupted' flag is set for the request. When + the request has been successfully transfered to userspace and + this flag is set, an INTERRUPT request is queued. + + 3) If the request is already sent to userspace, then an INTERRUPT + request is queued. + +INTERRUPT requests take precedence over other requests, so the +userspace filesystem will receive queued INTERRUPTs before any others. + +The userspace filesystem may ignore the INTERRUPT requests entirely, +or may honor them by sending a reply to the _original_ request, with +the error set to EINTR. + +It is also possible that there's a race between processing the +original request and it's INTERRUPT request. There are two possibilities: + + 1) The INTERRUPT request is processed before the original request is + processed + + 2) The INTERRUPT request is processed after the original request has + been answered + +If the filesystem cannot find the original request, it should wait for +some timeout and/or a number of new requests to arrive, after which it +should reply to the INTERRUPT request with an EAGAIN error. In case +1) the INTERRUPT request will be requeued. In case 2) the INTERRUPT +reply will be ignored. + Aborting a filesystem connection ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -351,10 +391,10 @@ but is caused by a pagefault. Solution is basically the same as above. -An additional problem is that while the write buffer is being -copied to the request, the request must not be interrupted. This -is because the destination address of the copy may not be valid -after the request is interrupted. +An additional problem is that while the write buffer is being copied +to the request, the request must not be interrupted/aborted. This is +because the destination address of the copy may not be valid after the +request has returned. This is solved with doing the copy atomically, and allowing abort while the page(s) belonging to the write buffer are faulted with diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 6b5f74cb7b54..1e2006caf158 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -34,6 +34,7 @@ static void fuse_request_init(struct fuse_req *req) { memset(req, 0, sizeof(*req)); INIT_LIST_HEAD(&req->list); + INIT_LIST_HEAD(&req->intr_entry); init_waitqueue_head(&req->waitq); atomic_set(&req->count, 1); } @@ -215,6 +216,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req) void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; req->end = NULL; list_del(&req->list); + list_del(&req->intr_entry); req->state = FUSE_REQ_FINISHED; if (req->background) { if (fc->num_background == FUSE_MAX_BACKGROUND) { @@ -235,28 +237,63 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req) fuse_put_request(fc, req); } +static void wait_answer_interruptible(struct fuse_conn *fc, + struct fuse_req *req) +{ + if (signal_pending(current)) + return; + + spin_unlock(&fc->lock); + wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED); + spin_lock(&fc->lock); +} + +static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req) +{ + list_add_tail(&req->intr_entry, &fc->interrupts); + wake_up(&fc->waitq); + kill_fasync(&fc->fasync, SIGIO, POLL_IN); +} + /* Called with fc->lock held. Releases, and then reacquires it. */ static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) { - sigset_t oldset; + if (!fc->no_interrupt) { + /* Any signal may interrupt this */ + wait_answer_interruptible(fc, req); - spin_unlock(&fc->lock); - if (req->force) + if (req->aborted) + goto aborted; + if (req->state == FUSE_REQ_FINISHED) + return; + + req->interrupted = 1; + if (req->state == FUSE_REQ_SENT) + queue_interrupt(fc, req); + } + + if (req->force) { + spin_unlock(&fc->lock); wait_event(req->waitq, req->state == FUSE_REQ_FINISHED); - else { + spin_lock(&fc->lock); + } else { + sigset_t oldset; + + /* Only fatal signals may interrupt this */ block_sigs(&oldset); - wait_event_interruptible(req->waitq, - req->state == FUSE_REQ_FINISHED); + wait_answer_interruptible(fc, req); restore_sigs(&oldset); } - spin_lock(&fc->lock); - if (req->state == FUSE_REQ_FINISHED && !req->aborted) - return; - if (!req->aborted) { - req->out.h.error = -EINTR; - req->aborted = 1; - } + if (req->aborted) + goto aborted; + if (req->state == FUSE_REQ_FINISHED) + return; + + req->out.h.error = -EINTR; + req->aborted = 1; + + aborted: if (req->locked) { /* This is uninterruptible sleep, because data is being copied to/from the buffers of req. During @@ -288,13 +325,19 @@ static unsigned len_args(unsigned numargs, struct fuse_arg *args) return nbytes; } +static u64 fuse_get_unique(struct fuse_conn *fc) + { + fc->reqctr++; + /* zero is special */ + if (fc->reqctr == 0) + fc->reqctr = 1; + + return fc->reqctr; +} + static void queue_request(struct fuse_conn *fc, struct fuse_req *req) { - fc->reqctr++; - /* zero is special */ - if (fc->reqctr == 0) - fc->reqctr = 1; - req->in.h.unique = fc->reqctr; + req->in.h.unique = fuse_get_unique(fc); req->in.h.len = sizeof(struct fuse_in_header) + len_args(req->in.numargs, (struct fuse_arg *) req->in.args); list_add_tail(&req->list, &fc->pending); @@ -307,9 +350,6 @@ static void queue_request(struct fuse_conn *fc, struct fuse_req *req) kill_fasync(&fc->fasync, SIGIO, POLL_IN); } -/* - * This can only be interrupted by a SIGKILL - */ void request_send(struct fuse_conn *fc, struct fuse_req *req) { req->isreply = 1; @@ -566,13 +606,18 @@ static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, return err; } +static int request_pending(struct fuse_conn *fc) +{ + return !list_empty(&fc->pending) || !list_empty(&fc->interrupts); +} + /* Wait until a request is available on the pending list */ static void request_wait(struct fuse_conn *fc) { DECLARE_WAITQUEUE(wait, current); add_wait_queue_exclusive(&fc->waitq, &wait); - while (fc->connected && list_empty(&fc->pending)) { + while (fc->connected && !request_pending(fc)) { set_current_state(TASK_INTERRUPTIBLE); if (signal_pending(current)) break; @@ -585,6 +630,45 @@ static void request_wait(struct fuse_conn *fc) remove_wait_queue(&fc->waitq, &wait); } +/* + * Transfer an interrupt request to userspace + * + * Unlike other requests this is assembled on demand, without a need + * to allocate a separate fuse_req structure. + * + * Called with fc->lock held, releases it + */ +static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req, + const struct iovec *iov, unsigned long nr_segs) +{ + struct fuse_copy_state cs; + struct fuse_in_header ih; + struct fuse_interrupt_in arg; + unsigned reqsize = sizeof(ih) + sizeof(arg); + int err; + + list_del_init(&req->intr_entry); + req->intr_unique = fuse_get_unique(fc); + memset(&ih, 0, sizeof(ih)); + memset(&arg, 0, sizeof(arg)); + ih.len = reqsize; + ih.opcode = FUSE_INTERRUPT; + ih.unique = req->intr_unique; + arg.unique = req->in.h.unique; + + spin_unlock(&fc->lock); + if (iov_length(iov, nr_segs) < reqsize) + return -EINVAL; + + fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs); + err = fuse_copy_one(&cs, &ih, sizeof(ih)); + if (!err) + err = fuse_copy_one(&cs, &arg, sizeof(arg)); + fuse_copy_finish(&cs); + + return err ? err : reqsize; +} + /* * Read a single request into the userspace filesystem's buffer. This * function waits until a request is available, then removes it from @@ -610,7 +694,7 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov, spin_lock(&fc->lock); err = -EAGAIN; if ((file->f_flags & O_NONBLOCK) && fc->connected && - list_empty(&fc->pending)) + !request_pending(fc)) goto err_unlock; request_wait(fc); @@ -618,9 +702,15 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov, if (!fc->connected) goto err_unlock; err = -ERESTARTSYS; - if (list_empty(&fc->pending)) + if (!request_pending(fc)) goto err_unlock; + if (!list_empty(&fc->interrupts)) { + req = list_entry(fc->interrupts.next, struct fuse_req, + intr_entry); + return fuse_read_interrupt(fc, req, iov, nr_segs); + } + req = list_entry(fc->pending.next, struct fuse_req, list); req->state = FUSE_REQ_READING; list_move(&req->list, &fc->io); @@ -658,6 +748,8 @@ static ssize_t fuse_dev_readv(struct file *file, const struct iovec *iov, else { req->state = FUSE_REQ_SENT; list_move_tail(&req->list, &fc->processing); + if (req->interrupted) + queue_interrupt(fc, req); spin_unlock(&fc->lock); } return reqsize; @@ -684,7 +776,7 @@ static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique) list_for_each(entry, &fc->processing) { struct fuse_req *req; req = list_entry(entry, struct fuse_req, list); - if (req->in.h.unique == unique) + if (req->in.h.unique == unique || req->intr_unique == unique) return req; } return NULL; @@ -750,7 +842,6 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov, goto err_unlock; req = request_find(fc, oh.unique); - err = -EINVAL; if (!req) goto err_unlock; @@ -761,6 +852,23 @@ static ssize_t fuse_dev_writev(struct file *file, const struct iovec *iov, request_end(fc, req); return -ENOENT; } + /* Is it an interrupt reply? */ + if (req->intr_unique == oh.unique) { + err = -EINVAL; + if (nbytes != sizeof(struct fuse_out_header)) + goto err_unlock; + + if (oh.error == -ENOSYS) + fc->no_interrupt = 1; + else if (oh.error == -EAGAIN) + queue_interrupt(fc, req); + + spin_unlock(&fc->lock); + fuse_copy_finish(&cs); + return nbytes; + } + + req->state = FUSE_REQ_WRITING; list_move(&req->list, &fc->io); req->out.h = oh; req->locked = 1; @@ -809,7 +917,7 @@ static unsigned fuse_dev_poll(struct file *file, poll_table *wait) spin_lock(&fc->lock); if (!fc->connected) mask = POLLERR; - else if (!list_empty(&fc->pending)) + else if (request_pending(fc)) mask |= POLLIN | POLLRDNORM; spin_unlock(&fc->lock); diff --git a/fs/fuse/file.c b/fs/fuse/file.c index ce759414cff9..36f92f181d2f 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -705,6 +705,9 @@ static int fuse_setlk(struct file *file, struct file_lock *fl) fuse_lk_fill(req, file, fl, opcode, pid); request_send(fc, req); err = req->out.h.error; + /* locking is restartable */ + if (err == -EINTR) + err = -ERESTARTSYS; fuse_put_request(fc, req); return err; } diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index fd65e75e1622..c862df58da92 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -131,6 +131,7 @@ enum fuse_req_state { FUSE_REQ_PENDING, FUSE_REQ_READING, FUSE_REQ_SENT, + FUSE_REQ_WRITING, FUSE_REQ_FINISHED }; @@ -144,9 +145,15 @@ struct fuse_req { fuse_conn */ struct list_head list; + /** Entry on the interrupts list */ + struct list_head intr_entry; + /** refcount */ atomic_t count; + /** Unique ID for the interrupt request */ + u64 intr_unique; + /* * The following bitfields are either set once before the * request is queued or setting/clearing them is protected by @@ -165,6 +172,9 @@ struct fuse_req { /** Request is sent in the background */ unsigned background:1; + /** The request has been interrupted */ + unsigned interrupted:1; + /** Data is being copied to/from the request */ unsigned locked:1; @@ -262,6 +272,9 @@ struct fuse_conn { /** Number of requests currently in the background */ unsigned num_background; + /** Pending interrupts */ + struct list_head interrupts; + /** Flag indicating if connection is blocked. This will be the case before the INIT reply is received, and if there are too many outstading backgrounds requests */ @@ -320,6 +333,9 @@ struct fuse_conn { /** Is create not implemented by fs? */ unsigned no_create : 1; + /** Is interrupt not implemented by fs? */ + unsigned no_interrupt : 1; + /** The number of requests waiting for completion */ atomic_t num_waiting; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 412892905838..e21ef8a3ad30 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -381,6 +381,7 @@ static struct fuse_conn *new_conn(void) INIT_LIST_HEAD(&fc->pending); INIT_LIST_HEAD(&fc->processing); INIT_LIST_HEAD(&fc->io); + INIT_LIST_HEAD(&fc->interrupts); atomic_set(&fc->num_waiting, 0); fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; fc->bdi.unplug_io_fn = default_unplug_io_fn; diff --git a/include/linux/fuse.h b/include/linux/fuse.h index e7a76ec0f05c..9fc48a674b82 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -125,7 +125,8 @@ enum fuse_opcode { FUSE_SETLK = 32, FUSE_SETLKW = 33, FUSE_ACCESS = 34, - FUSE_CREATE = 35 + FUSE_CREATE = 35, + FUSE_INTERRUPT = 36, }; /* The read buffer is required to be at least 8k, but may be much larger */ @@ -291,6 +292,10 @@ struct fuse_init_out { __u32 max_write; }; +struct fuse_interrupt_in { + __u64 unique; +}; + struct fuse_in_header { __u32 len; __u32 opcode; -- cgit v1.2.3 From 9c8ef5614da22666e339b125263d315cfaa89109 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Sun, 25 Jun 2006 05:48:55 -0700 Subject: [PATCH] fuse: scramble lock owner ID VFS uses current->files pointer as lock owner ID, and it wouldn't be prudent to expose this value to userspace. So scramble it with XTEA using a per connection random key, known only to the kernel. Only one direction needs to be implemented, since the ID is never sent in the reverse direction. The XTEA algorithm is implemented inline since it's simple enough to do so, and this adds less complexity than if the crypto API were used. Thanks to Jesper Juhl for the idea. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/file.c | 29 ++++++++++++++++++++--------- fs/fuse/fuse_i.h | 3 +++ fs/fuse/inode.c | 2 ++ 3 files changed, 25 insertions(+), 9 deletions(-) (limited to 'fs/fuse/fuse_i.h') diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 36f92f181d2f..28aa81eae2cc 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -161,15 +161,25 @@ static int fuse_release(struct inode *inode, struct file *file) } /* - * It would be nice to scramble the ID space, so that the value of the - * files_struct pointer is not exposed to userspace. Symmetric crypto - * functions are overkill, since the inverse function doesn't need to - * be implemented (though it does have to exist). Is there something - * simpler? + * Scramble the ID space with XTEA, so that the value of the files_struct + * pointer is not exposed to userspace. */ -static inline u64 fuse_lock_owner_id(fl_owner_t id) +static u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id) { - return (unsigned long) id; + u32 *k = fc->scramble_key; + u64 v = (unsigned long) id; + u32 v0 = v; + u32 v1 = v >> 32; + u32 sum = 0; + int i; + + for (i = 0; i < 32; i++) { + v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]); + sum += 0x9E3779B9; + v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]); + } + + return (u64) v0 + ((u64) v1 << 32); } static int fuse_flush(struct file *file, fl_owner_t id) @@ -190,7 +200,7 @@ static int fuse_flush(struct file *file, fl_owner_t id) req = fuse_get_req_nofail(fc, file); memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; - inarg.lock_owner = fuse_lock_owner_id(id); + inarg.lock_owner = fuse_lock_owner_id(fc, id); req->in.h.opcode = FUSE_FLUSH; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; @@ -644,11 +654,12 @@ static void fuse_lk_fill(struct fuse_req *req, struct file *file, const struct file_lock *fl, int opcode, pid_t pid) { struct inode *inode = file->f_dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; struct fuse_lk_in *arg = &req->misc.lk_in; arg->fh = ff->fh; - arg->owner = fuse_lock_owner_id(fl->fl_owner); + arg->owner = fuse_lock_owner_id(fc, fl->fl_owner); arg->lk.start = fl->fl_start; arg->lk.end = fl->fl_end; arg->lk.type = fl->fl_type; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index c862df58da92..0dbf96621841 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -359,6 +359,9 @@ struct fuse_conn { /** O_ASYNC requests */ struct fasync_struct *fasync; + + /** Key for lock owner ID scrambling */ + u32 scramble_key[4]; }; static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index e21ef8a3ad30..5ceb8bd7a189 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -16,6 +16,7 @@ #include #include #include +#include MODULE_AUTHOR("Miklos Szeredi "); MODULE_DESCRIPTION("Filesystem in Userspace"); @@ -387,6 +388,7 @@ static struct fuse_conn *new_conn(void) fc->bdi.unplug_io_fn = default_unplug_io_fn; fc->reqctr = 0; fc->blocked = 1; + get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); } return fc; } -- cgit v1.2.3