From c744aeae9d173a953b771a7ad5c872f91fa99dec Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Mon, 8 Jan 2007 20:16:44 +0100 Subject: driver core: Allow device_move(dev, NULL). If we allow NULL as the new parent in device_move(), we need to make sure that the device is placed into the same place as it would if it was newly registered: - Consider the device virtual tree. In order to be able to reuse code, setup_parent() has been tweaked a bit. - kobject_move() can fall back to the kset's kobject. - sysfs_move_dir() uses the sysfs root dir as fallback. Signed-off-by: Cornelia Huck Cc: Marcel Holtmann Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'fs/sysfs') diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 511edef8b321..2bab1b4ddf5a 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -378,12 +378,10 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent) struct sysfs_dirent *new_parent_sd, *sd; int error; - if (!new_parent) - return -EINVAL; - old_parent_dentry = kobj->parent ? kobj->parent->dentry : sysfs_mount->mnt_sb->s_root; - new_parent_dentry = new_parent->dentry; + new_parent_dentry = new_parent ? + new_parent->dentry : sysfs_mount->mnt_sb->s_root; again: mutex_lock(&old_parent_dentry->d_inode->i_mutex); -- cgit v1.2.2 From 94bebf4d1b8e7719f0f3944c037a21cfd99a4af7 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 20 Dec 2006 10:52:44 +0100 Subject: Driver core: fix race in sysfs between sysfs_remove_file() and read()/write() This patch prevents a race between IO and removing a file from sysfs. It introduces a list of sysfs_buffers associated with a file at the inode. Upon removal of a file the list is walked and the buffers marked orphaned. IO to orphaned buffers fails with -ENODEV. The driver can safely free associated data structures or be unloaded. Signed-off-by: Oliver Neukum Acked-by: Maneesh Soni Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/bin.c | 1 + fs/sysfs/dir.c | 1 + fs/sysfs/file.c | 67 ++++++++++++++++++++++++++++++++++++++++-------------- fs/sysfs/group.c | 1 + fs/sysfs/inode.c | 24 +++++++++++++++++++ fs/sysfs/mount.c | 9 ++++++++ fs/sysfs/symlink.c | 1 + fs/sysfs/sysfs.h | 16 +++++++++++++ 8 files changed, 103 insertions(+), 17 deletions(-) (limited to 'fs/sysfs') diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c index e8f540d38d48..9ec1c8539a5d 100644 --- a/fs/sysfs/bin.c +++ b/fs/sysfs/bin.c @@ -16,6 +16,7 @@ #include #include +#include #include "sysfs.h" diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 2bab1b4ddf5a..9ff04491e3ea 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -9,6 +9,7 @@ #include #include #include +#include #include "sysfs.h" DECLARE_RWSEM(sysfs_rename_sem); diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 9cfe53e1e00d..cba4c1c7383c 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include @@ -50,17 +51,29 @@ static struct sysfs_ops subsys_sysfs_ops = { .store = subsys_attr_store, }; +/** + * add_to_collection - add buffer to a collection + * @buffer: buffer to be added + * @node inode of set to add to + */ -struct sysfs_buffer { - size_t count; - loff_t pos; - char * page; - struct sysfs_ops * ops; - struct semaphore sem; - int needs_read_fill; - int event; -}; +static inline void +add_to_collection(struct sysfs_buffer *buffer, struct inode *node) +{ + struct sysfs_buffer_collection *set = node->i_private; + mutex_lock(&node->i_mutex); + list_add(&buffer->associates, &set->associates); + mutex_unlock(&node->i_mutex); +} + +static inline void +remove_from_collection(struct sysfs_buffer *buffer, struct inode *node) +{ + mutex_lock(&node->i_mutex); + list_del(&buffer->associates); + mutex_unlock(&node->i_mutex); +} /** * fill_read_buffer - allocate and fill buffer from object. @@ -153,6 +166,10 @@ sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) ssize_t retval = 0; down(&buffer->sem); + if (buffer->orphaned) { + retval = -ENODEV; + goto out; + } if (buffer->needs_read_fill) { if ((retval = fill_read_buffer(file->f_path.dentry,buffer))) goto out; @@ -165,7 +182,6 @@ out: return retval; } - /** * fill_write_buffer - copy buffer from userspace. * @buffer: data buffer for file. @@ -243,19 +259,25 @@ sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t ssize_t len; down(&buffer->sem); + if (buffer->orphaned) { + len = -ENODEV; + goto out; + } len = fill_write_buffer(buffer, buf, count); if (len > 0) len = flush_write_buffer(file->f_path.dentry, buffer, len); if (len > 0) *ppos += len; +out: up(&buffer->sem); return len; } -static int check_perm(struct inode * inode, struct file * file) +static int sysfs_open_file(struct inode *inode, struct file *file) { struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent); struct attribute * attr = to_attr(file->f_path.dentry); + struct sysfs_buffer_collection *set; struct sysfs_buffer * buffer; struct sysfs_ops * ops = NULL; int error = 0; @@ -285,6 +307,18 @@ static int check_perm(struct inode * inode, struct file * file) if (!ops) goto Eaccess; + /* make sure we have a collection to add our buffers to */ + mutex_lock(&inode->i_mutex); + if (!(set = inode->i_private)) { + if (!(set = inode->i_private = kmalloc(sizeof(struct sysfs_buffer_collection), GFP_KERNEL))) { + error = -ENOMEM; + goto Done; + } else { + INIT_LIST_HEAD(&set->associates); + } + } + mutex_unlock(&inode->i_mutex); + /* File needs write support. * The inode's perms must say it's ok, * and we must have a store method. @@ -310,9 +344,11 @@ static int check_perm(struct inode * inode, struct file * file) */ buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); if (buffer) { + INIT_LIST_HEAD(&buffer->associates); init_MUTEX(&buffer->sem); buffer->needs_read_fill = 1; buffer->ops = ops; + add_to_collection(buffer, inode); file->private_data = buffer; } else error = -ENOMEM; @@ -330,11 +366,6 @@ static int check_perm(struct inode * inode, struct file * file) return error; } -static int sysfs_open_file(struct inode * inode, struct file * filp) -{ - return check_perm(inode,filp); -} - static int sysfs_release(struct inode * inode, struct file * filp) { struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent); @@ -342,6 +373,8 @@ static int sysfs_release(struct inode * inode, struct file * filp) struct module * owner = attr->owner; struct sysfs_buffer * buffer = filp->private_data; + if (buffer) + remove_from_collection(buffer, inode); if (kobj) kobject_put(kobj); /* After this point, attr should not be accessed. */ @@ -548,7 +581,7 @@ EXPORT_SYMBOL_GPL(sysfs_chmod_file); void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) { - sysfs_hash_and_remove(kobj->dentry,attr->name); + sysfs_hash_and_remove(kobj->dentry, attr->name); } diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index 122145b0895c..46a277b0838e 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "sysfs.h" diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index e79e38d52c00..1a81ebce20e9 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "sysfs.h" extern struct super_block * sysfs_sb; @@ -209,6 +210,22 @@ const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) return NULL; } +static inline void orphan_all_buffers(struct inode *node) +{ + struct sysfs_buffer_collection *set = node->i_private; + struct sysfs_buffer *buf; + + mutex_lock(&node->i_mutex); + if (node->i_private) { + list_for_each_entry(buf, &set->associates, associates) { + down(&buf->sem); + buf->orphaned = 1; + up(&buf->sem); + } + } + mutex_unlock(&node->i_mutex); +} + /* * Unhashes the dentry corresponding to given sysfs_dirent @@ -217,16 +234,23 @@ const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent) { struct dentry * dentry = sd->s_dentry; + struct inode *inode; if (dentry) { spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); if (!(d_unhashed(dentry) && dentry->d_inode)) { + inode = dentry->d_inode; + spin_lock(&inode->i_lock); + __iget(inode); + spin_unlock(&inode->i_lock); dget_locked(dentry); __d_drop(dentry); spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); simple_unlink(parent->d_inode, dentry); + orphan_all_buffers(inode); + iput(inode); } else { spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index e503f858fba8..a1a58b97f322 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -8,6 +8,7 @@ #include #include #include +#include #include "sysfs.h" @@ -18,9 +19,12 @@ struct vfsmount *sysfs_mount; struct super_block * sysfs_sb = NULL; struct kmem_cache *sysfs_dir_cachep; +static void sysfs_clear_inode(struct inode *inode); + static struct super_operations sysfs_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, + .clear_inode = sysfs_clear_inode, }; static struct sysfs_dirent sysfs_root = { @@ -31,6 +35,11 @@ static struct sysfs_dirent sysfs_root = { .s_iattr = NULL, }; +static void sysfs_clear_inode(struct inode *inode) +{ + kfree(inode->i_private); +} + static int sysfs_fill_super(struct super_block *sb, void *data, int silent) { struct inode *inode; diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c index f50e3cc2ded8..4869f611192f 100644 --- a/fs/sysfs/symlink.c +++ b/fs/sysfs/symlink.c @@ -7,6 +7,7 @@ #include #include #include +#include #include "sysfs.h" diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index bd7cec295dab..39c623fdc277 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -33,6 +33,22 @@ struct sysfs_symlink { struct kobject * target_kobj; }; +struct sysfs_buffer { + struct list_head associates; + size_t count; + loff_t pos; + char * page; + struct sysfs_ops * ops; + struct semaphore sem; + int orphaned; + int needs_read_fill; + int event; +}; + +struct sysfs_buffer_collection { + struct list_head associates; +}; + static inline struct kobject * to_kobj(struct dentry * dentry) { struct sysfs_dirent * sd = dentry->d_fsdata; -- cgit v1.2.2 From d3fc373ac5061cab7a654502b942e7d00e77f733 Mon Sep 17 00:00:00 2001 From: Frederik Deweerdt Date: Fri, 5 Jan 2007 12:04:33 -0800 Subject: sysfs: suppress lockdep warnings Lockdep issues the following warning: [ 9.064000] ============================================= [ 9.064000] [ INFO: possible recursive locking detected ] [ 9.064000] 2.6.20-rc3-mm1 #3 [ 9.064000] --------------------------------------------- [ 9.064000] init/1 is trying to acquire lock: [ 9.064000] (&sysfs_inode_imutex_key){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.064000] [ 9.064000] but task is already holding lock: [ 9.064000] (&sysfs_inode_imutex_key){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.065000] [ 9.065000] other info that might help us debug this: [ 9.065000] 2 locks held by init/1: [ 9.065000] #0: (tty_mutex){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.065000] #1: (&sysfs_inode_imutex_key){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.065000] [ 9.065000] stack backtrace: [ 9.065000] [] show_trace_log_lvl+0x1a/0x30 [ 9.066000] [] show_trace+0x12/0x14 [ 9.066000] [] dump_stack+0x16/0x18 [ 9.066000] [] print_deadlock_bug+0xb9/0xc3 [ 9.066000] [] check_deadlock+0x55/0x5a [ 9.066000] [] __lock_acquire+0x371/0xbf0 [ 9.066000] [] lock_acquire+0x69/0x83 [ 9.066000] [] __mutex_lock_slowpath+0x75/0x2d1 [ 9.066000] [] mutex_lock+0x1c/0x1f [ 9.066000] [] sysfs_drop_dentry+0xb1/0x133 [ 9.066000] [] sysfs_hash_and_remove+0xb3/0x142 [ 9.066000] [] sysfs_remove_file+0xd/0x10 [ 9.067000] [] device_remove_file+0x23/0x2e [ 9.067000] [] device_del+0x188/0x1e6 [ 9.067000] [] device_unregister+0xb/0x15 [ 9.067000] [] device_destroy+0x9c/0xa9 [ 9.067000] [] vcs_remove_sysfs+0x1c/0x3b [ 9.067000] [] con_close+0x5e/0x6b [ 9.067000] [] release_dev+0x4c4/0x6e5 [ 9.067000] [] tty_release+0x12/0x1c [ 9.067000] [] __fput+0x177/0x1a0 [ 9.067000] [] fput+0x3b/0x41 [ 9.068000] [] filp_close+0x36/0x65 [ 9.068000] [] sys_close+0x63/0xa4 [ 9.068000] [] sysenter_past_esp+0x5f/0x99 [ 9.068000] ======================= This is due to sysfs_hash_and_remove() holding dir->d_inode->i_mutex before calling sysfs_drop_dentry() which calls orphan_all_buffers() which in turn takes node->i_mutex. Signed-off-by: Frederik Deweerdt Cc: Oliver Neukum Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/sysfs') diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index 1a81ebce20e9..dbd820f9aeed 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -215,7 +215,7 @@ static inline void orphan_all_buffers(struct inode *node) struct sysfs_buffer_collection *set = node->i_private; struct sysfs_buffer *buf; - mutex_lock(&node->i_mutex); + mutex_lock_nested(&node->i_mutex, I_MUTEX_CHILD); if (node->i_private) { list_for_each_entry(buf, &set->associates, associates) { down(&buf->sem); @@ -272,7 +272,7 @@ int sysfs_hash_and_remove(struct dentry * dir, const char * name) return -ENOENT; parent_sd = dir->d_fsdata; - mutex_lock(&dir->d_inode->i_mutex); + mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { if (!sd->s_element) continue; -- cgit v1.2.2 From f75065367077bd3b77842a5aa523ecd05d33e82d Mon Sep 17 00:00:00 2001 From: Mariusz Kozlowski Date: Tue, 2 Jan 2007 13:41:10 +0100 Subject: sysfs: kobject_put cleanup This patch removes redundant argument checks for kobject_put(). Signed-off-by: Mariusz Kozlowski Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/bin.c | 5 ++--- fs/sysfs/file.c | 5 ++--- 2 files changed, 4 insertions(+), 6 deletions(-) (limited to 'fs/sysfs') diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c index 9ec1c8539a5d..d3b9f5f07db1 100644 --- a/fs/sysfs/bin.c +++ b/fs/sysfs/bin.c @@ -147,7 +147,7 @@ static int open(struct inode * inode, struct file * file) Error: module_put(attr->attr.owner); Done: - if (error && kobj) + if (error) kobject_put(kobj); return error; } @@ -158,8 +158,7 @@ static int release(struct inode * inode, struct file * file) struct bin_attribute * attr = to_bin_attr(file->f_path.dentry); u8 * buffer = file->private_data; - if (kobj) - kobject_put(kobj); + kobject_put(kobj); module_put(attr->attr.owner); kfree(buffer); return 0; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index cba4c1c7383c..46618f81ae48 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -361,7 +361,7 @@ static int sysfs_open_file(struct inode *inode, struct file *file) error = -EACCES; module_put(attr->owner); Done: - if (error && kobj) + if (error) kobject_put(kobj); return error; } @@ -375,8 +375,7 @@ static int sysfs_release(struct inode * inode, struct file * filp) if (buffer) remove_from_collection(buffer, inode); - if (kobj) - kobject_put(kobj); + kobject_put(kobj); /* After this point, attr should not be accessed. */ module_put(owner); -- cgit v1.2.2 From 82244b169ed2eee1ef7f97a3a6693f5a6eff8a69 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Tue, 2 Jan 2007 08:48:08 +0100 Subject: sysfs: error handling in sysfs, fill_read_buffer() if a driver returns an error in fill_read_buffer(), the buffer will be marked as filled. Subsequent reads will return eof. But there is no data because of an error, not because it has been read. Not marking the buffer filled is the obvious fix. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/file.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'fs/sysfs') diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 46618f81ae48..c0e117649a4d 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -83,7 +83,8 @@ remove_from_collection(struct sysfs_buffer *buffer, struct inode *node) * Allocate @buffer->page, if it hasn't been already, then call the * kobject's show() method to fill the buffer with this attribute's * data. - * This is called only once, on the file's first read. + * This is called only once, on the file's first read unless an error + * is returned. */ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer) { @@ -101,12 +102,13 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer buffer->event = atomic_read(&sd->s_event); count = ops->show(kobj,attr,buffer->page); - buffer->needs_read_fill = 0; BUG_ON(count > (ssize_t)PAGE_SIZE); - if (count >= 0) + if (count >= 0) { + buffer->needs_read_fill = 0; buffer->count = count; - else + } else { ret = count; + } return ret; } -- cgit v1.2.2 From b592fcfe7f06c15ec11774b5be7ce0de3aa86e73 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 24 Jan 2007 12:35:52 -0700 Subject: sysfs: Shadow directory support The problem. When implementing a network namespace I need to be able to have multiple network devices with the same name. Currently this is a problem for /sys/class/net/*. What I want is a separate /sys/class/net directory in sysfs for each network namespace, and I want to name each of them /sys/class/net. I looked and the VFS actually allows that. All that is needed is for /sys/class/net to implement a follow link method to redirect lookups to the real directory you want. Implementing a follow link method that is sensitive to the current network namespace turns out to be 3 lines of code so it looks like a clean approach. Modifying sysfs so it doesn't get in my was is a bit trickier. I am calling the concept of multiple directories all at the same path in the filesystem shadow directories. With the directory entry really at that location the shadow master. The following patch modifies sysfs so it can handle a directory structure slightly different from the kobject tree so I can implement the shadow directories for handling /sys/class/net/. Signed-off-by: Eric W. Biederman Cc: Maneesh Soni Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/dir.c | 207 +++++++++++++++++++++++++++++++++++++++++++++---------- fs/sysfs/group.c | 1 + fs/sysfs/inode.c | 10 +++ fs/sysfs/mount.c | 2 +- fs/sysfs/sysfs.h | 5 ++ 5 files changed, 189 insertions(+), 36 deletions(-) (limited to 'fs/sysfs') diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 9ff04491e3ea..9dcdf556c99c 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -33,8 +33,7 @@ static struct dentry_operations sysfs_dentry_ops = { /* * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent */ -static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd, - void * element) +static struct sysfs_dirent * __sysfs_new_dirent(void * element) { struct sysfs_dirent * sd; @@ -46,12 +45,28 @@ static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent * parent_sd, atomic_set(&sd->s_count, 1); atomic_set(&sd->s_event, 1); INIT_LIST_HEAD(&sd->s_children); - list_add(&sd->s_sibling, &parent_sd->s_children); + INIT_LIST_HEAD(&sd->s_sibling); sd->s_element = element; return sd; } +static void __sysfs_list_dirent(struct sysfs_dirent *parent_sd, + struct sysfs_dirent *sd) +{ + if (sd) + list_add(&sd->s_sibling, &parent_sd->s_children); +} + +static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent *parent_sd, + void * element) +{ + struct sysfs_dirent *sd; + sd = __sysfs_new_dirent(element); + __sysfs_list_dirent(parent_sd, sd); + return sd; +} + /* * * Return -EEXIST if there is already a sysfs element with the same name for @@ -78,14 +93,14 @@ int sysfs_dirent_exist(struct sysfs_dirent *parent_sd, } -int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry, - void * element, umode_t mode, int type) +static struct sysfs_dirent * +__sysfs_make_dirent(struct dentry *dentry, void *element, mode_t mode, int type) { struct sysfs_dirent * sd; - sd = sysfs_new_dirent(parent_sd, element); + sd = __sysfs_new_dirent(element); if (!sd) - return -ENOMEM; + goto out; sd->s_mode = mode; sd->s_type = type; @@ -95,7 +110,19 @@ int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry, dentry->d_op = &sysfs_dentry_ops; } - return 0; +out: + return sd; +} + +int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry, + void * element, umode_t mode, int type) +{ + struct sysfs_dirent *sd; + + sd = __sysfs_make_dirent(dentry, element, mode, type); + __sysfs_list_dirent(parent_sd, sd); + + return sd ? 0 : -ENOMEM; } static int init_dir(struct inode * inode) @@ -166,11 +193,11 @@ int sysfs_create_subdir(struct kobject * k, const char * n, struct dentry ** d) /** * sysfs_create_dir - create a directory for an object. - * @parent: parent parent object. * @kobj: object we're creating directory for. + * @shadow_parent: parent parent object. */ -int sysfs_create_dir(struct kobject * kobj) +int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent) { struct dentry * dentry = NULL; struct dentry * parent; @@ -178,7 +205,9 @@ int sysfs_create_dir(struct kobject * kobj) BUG_ON(!kobj); - if (kobj->parent) + if (shadow_parent) + parent = shadow_parent; + else if (kobj->parent) parent = kobj->parent->dentry; else if (sysfs_mount && sysfs_mount->mnt_sb) parent = sysfs_mount->mnt_sb->s_root; @@ -299,21 +328,12 @@ void sysfs_remove_subdir(struct dentry * d) } -/** - * sysfs_remove_dir - remove an object's directory. - * @kobj: object. - * - * The only thing special about this is that we remove any files in - * the directory before we remove the directory, and we've inlined - * what used to be sysfs_rmdir() below, instead of calling separately. - */ - -void sysfs_remove_dir(struct kobject * kobj) +static void __sysfs_remove_dir(struct dentry *dentry) { - struct dentry * dentry = dget(kobj->dentry); struct sysfs_dirent * parent_sd; struct sysfs_dirent * sd, * tmp; + dget(dentry); if (!dentry) return; @@ -334,32 +354,60 @@ void sysfs_remove_dir(struct kobject * kobj) * Drop reference from dget() on entrance. */ dput(dentry); +} + +/** + * sysfs_remove_dir - remove an object's directory. + * @kobj: object. + * + * The only thing special about this is that we remove any files in + * the directory before we remove the directory, and we've inlined + * what used to be sysfs_rmdir() below, instead of calling separately. + */ + +void sysfs_remove_dir(struct kobject * kobj) +{ + __sysfs_remove_dir(kobj->dentry); kobj->dentry = NULL; } -int sysfs_rename_dir(struct kobject * kobj, const char *new_name) +int sysfs_rename_dir(struct kobject * kobj, struct dentry *new_parent, + const char *new_name) { int error = 0; - struct dentry * new_dentry, * parent; + struct dentry * new_dentry; - if (!strcmp(kobject_name(kobj), new_name)) - return -EINVAL; - - if (!kobj->parent) - return -EINVAL; + if (!new_parent) + return -EFAULT; down_write(&sysfs_rename_sem); - parent = kobj->parent->dentry; + mutex_lock(&new_parent->d_inode->i_mutex); - mutex_lock(&parent->d_inode->i_mutex); - - new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); + new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); if (!IS_ERR(new_dentry)) { - if (!new_dentry->d_inode) { + /* By allowing two different directories with the + * same d_parent we allow this routine to move + * between different shadows of the same directory + */ + if (kobj->dentry->d_parent->d_inode != new_parent->d_inode) + return -EINVAL; + else if (new_dentry->d_parent->d_inode != new_parent->d_inode) + error = -EINVAL; + else if (new_dentry == kobj->dentry) + error = -EINVAL; + else if (!new_dentry->d_inode) { error = kobject_set_name(kobj, "%s", new_name); if (!error) { + struct sysfs_dirent *sd, *parent_sd; + d_add(new_dentry, NULL); d_move(kobj->dentry, new_dentry); + + sd = kobj->dentry->d_fsdata; + parent_sd = new_parent->d_fsdata; + + list_del_init(&sd->s_sibling); + list_add(&sd->s_sibling, &parent_sd->s_children); } else d_drop(new_dentry); @@ -367,7 +415,7 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name) error = -EEXIST; dput(new_dentry); } - mutex_unlock(&parent->d_inode->i_mutex); + mutex_unlock(&new_parent->d_inode->i_mutex); up_write(&sysfs_rename_sem); return error; @@ -546,6 +594,95 @@ static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin) return offset; } + +/** + * sysfs_make_shadowed_dir - Setup so a directory can be shadowed + * @kobj: object we're creating shadow of. + */ + +int sysfs_make_shadowed_dir(struct kobject *kobj, + void * (*follow_link)(struct dentry *, struct nameidata *)) +{ + struct inode *inode; + struct inode_operations *i_op; + + inode = kobj->dentry->d_inode; + if (inode->i_op != &sysfs_dir_inode_operations) + return -EINVAL; + + i_op = kmalloc(sizeof(*i_op), GFP_KERNEL); + if (!i_op) + return -ENOMEM; + + memcpy(i_op, &sysfs_dir_inode_operations, sizeof(*i_op)); + i_op->follow_link = follow_link; + + /* Locking of inode->i_op? + * Since setting i_op is a single word write and they + * are atomic we should be ok here. + */ + inode->i_op = i_op; + return 0; +} + +/** + * sysfs_create_shadow_dir - create a shadow directory for an object. + * @kobj: object we're creating directory for. + * + * sysfs_make_shadowed_dir must already have been called on this + * directory. + */ + +struct dentry *sysfs_create_shadow_dir(struct kobject *kobj) +{ + struct sysfs_dirent *sd; + struct dentry *parent, *dir, *shadow; + struct inode *inode; + + dir = kobj->dentry; + inode = dir->d_inode; + parent = dir->d_parent; + shadow = ERR_PTR(-EINVAL); + if (!sysfs_is_shadowed_inode(inode)) + goto out; + + shadow = d_alloc(parent, &dir->d_name); + if (!shadow) + goto nomem; + + sd = __sysfs_make_dirent(shadow, kobj, inode->i_mode, SYSFS_DIR); + if (!sd) + goto nomem; + + d_instantiate(shadow, igrab(inode)); + inc_nlink(inode); + inc_nlink(parent->d_inode); + shadow->d_op = &sysfs_dentry_ops; + + dget(shadow); /* Extra count - pin the dentry in core */ + +out: + return shadow; +nomem: + dput(shadow); + shadow = ERR_PTR(-ENOMEM); + goto out; +} + +/** + * sysfs_remove_shadow_dir - remove an object's directory. + * @shadow: dentry of shadow directory + * + * The only thing special about this is that we remove any files in + * the directory before we remove the directory, and we've inlined + * what used to be sysfs_rmdir() below, instead of calling separately. + */ + +void sysfs_remove_shadow_dir(struct dentry *shadow) +{ + __sysfs_remove_dir(shadow); +} + const struct file_operations sysfs_dir_operations = { .open = sysfs_dir_open, .release = sysfs_dir_close, diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index 46a277b0838e..b20951c93761 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include "sysfs.h" diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index dbd820f9aeed..542d2bcc73df 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -33,6 +33,16 @@ static struct inode_operations sysfs_inode_operations ={ .setattr = sysfs_setattr, }; +void sysfs_delete_inode(struct inode *inode) +{ + /* Free the shadowed directory inode operations */ + if (sysfs_is_shadowed_inode(inode)) { + kfree(inode->i_op); + inode->i_op = NULL; + } + return generic_delete_inode(inode); +} + int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) { struct inode * inode = dentry->d_inode; diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index a1a58b97f322..f6a87a824883 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -23,7 +23,7 @@ static void sysfs_clear_inode(struct inode *inode); static struct super_operations sysfs_ops = { .statfs = simple_statfs, - .drop_inode = generic_delete_inode, + .drop_inode = sysfs_delete_inode, .clear_inode = sysfs_clear_inode, }; diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 39c623fdc277..fe1cbfd208ed 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -2,6 +2,7 @@ extern struct vfsmount * sysfs_mount; extern struct kmem_cache *sysfs_dir_cachep; +extern void sysfs_delete_inode(struct inode *inode); extern struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *); extern int sysfs_create(struct dentry *, int mode, int (*init)(struct inode *)); @@ -112,3 +113,7 @@ static inline void sysfs_put(struct sysfs_dirent * sd) release_sysfs_dirent(sd); } +static inline int sysfs_is_shadowed_inode(struct inode *inode) +{ + return S_ISDIR(inode->i_mode) && inode->i_op->follow_link; +} -- cgit v1.2.2