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fs/libfs.c
26.7 KB
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/* * fs/libfs.c * Library for filesystems writers. */ |
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#include <linux/export.h> |
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#include <linux/pagemap.h> |
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#include <linux/slab.h> |
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#include <linux/mount.h> #include <linux/vfs.h> |
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#include <linux/quotaops.h> |
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#include <linux/mutex.h> |
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#include <linux/namei.h> |
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#include <linux/exportfs.h> |
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#include <linux/writeback.h> |
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#include <linux/buffer_head.h> /* sync_mapping_buffers */ |
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#include <asm/uaccess.h> |
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#include "internal.h" |
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static inline int simple_positive(struct dentry *dentry) { return dentry->d_inode && !d_unhashed(dentry); } |
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int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct inode *inode = dentry->d_inode; generic_fillattr(inode, stat); stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); return 0; } |
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EXPORT_SYMBOL(simple_getattr); |
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|
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int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
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{ |
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buf->f_type = dentry->d_sb->s_magic; |
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buf->f_bsize = PAGE_CACHE_SIZE; buf->f_namelen = NAME_MAX; return 0; } |
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EXPORT_SYMBOL(simple_statfs); |
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/* * Retaining negative dentries for an in-memory filesystem just wastes * memory and lookup time: arrange for them to be deleted immediately. */ |
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int always_delete_dentry(const struct dentry *dentry) |
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{ return 1; } |
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EXPORT_SYMBOL(always_delete_dentry); const struct dentry_operations simple_dentry_operations = { .d_delete = always_delete_dentry, }; EXPORT_SYMBOL(simple_dentry_operations); |
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/* * Lookup the data. This is trivial - if the dentry didn't already * exist, we know it is negative. Set d_op to delete negative dentries. */ |
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struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
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{ |
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if (dentry->d_name.len > NAME_MAX) return ERR_PTR(-ENAMETOOLONG); |
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if (!dentry->d_sb->s_d_op) d_set_d_op(dentry, &simple_dentry_operations); |
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d_add(dentry, NULL); return NULL; } |
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EXPORT_SYMBOL(simple_lookup); |
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int dcache_dir_open(struct inode *inode, struct file *file) { |
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static struct qstr cursor_name = QSTR_INIT(".", 1); |
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file->private_data = d_alloc(file->f_path.dentry, &cursor_name); |
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return file->private_data ? 0 : -ENOMEM; } |
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EXPORT_SYMBOL(dcache_dir_open); |
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int dcache_dir_close(struct inode *inode, struct file *file) { dput(file->private_data); return 0; } |
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EXPORT_SYMBOL(dcache_dir_close); |
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loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
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{ |
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struct dentry *dentry = file->f_path.dentry; mutex_lock(&dentry->d_inode->i_mutex); |
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switch (whence) { |
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case 1: offset += file->f_pos; case 0: if (offset >= 0) break; default: |
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mutex_unlock(&dentry->d_inode->i_mutex); |
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return -EINVAL; } if (offset != file->f_pos) { file->f_pos = offset; if (file->f_pos >= 2) { struct list_head *p; struct dentry *cursor = file->private_data; loff_t n = file->f_pos - 2; |
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spin_lock(&dentry->d_lock); /* d_lock not required for cursor */ |
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list_del(&cursor->d_u.d_child); |
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p = dentry->d_subdirs.next; while (n && p != &dentry->d_subdirs) { |
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struct dentry *next; |
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next = list_entry(p, struct dentry, d_u.d_child); |
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spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); |
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if (simple_positive(next)) |
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n--; |
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spin_unlock(&next->d_lock); |
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p = p->next; } |
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list_add_tail(&cursor->d_u.d_child, p); |
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spin_unlock(&dentry->d_lock); |
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} } |
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mutex_unlock(&dentry->d_inode->i_mutex); |
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return offset; } |
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EXPORT_SYMBOL(dcache_dir_lseek); |
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/* Relationship between i_mode and the DT_xxx types */ static inline unsigned char dt_type(struct inode *inode) { return (inode->i_mode >> 12) & 15; } /* * Directory is locked and all positive dentries in it are safe, since * for ramfs-type trees they can't go away without unlink() or rmdir(), * both impossible due to the lock on directory. */ |
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int dcache_readdir(struct file *file, struct dir_context *ctx) |
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{ |
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struct dentry *dentry = file->f_path.dentry; struct dentry *cursor = file->private_data; |
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struct list_head *p, *q = &cursor->d_u.d_child; |
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if (!dir_emit_dots(file, ctx)) return 0; spin_lock(&dentry->d_lock); if (ctx->pos == 2) list_move(q, &dentry->d_subdirs); for (p = q->next; p != &dentry->d_subdirs; p = p->next) { struct dentry *next = list_entry(p, struct dentry, d_u.d_child); spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); if (!simple_positive(next)) { spin_unlock(&next->d_lock); continue; } |
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spin_unlock(&next->d_lock); spin_unlock(&dentry->d_lock); if (!dir_emit(ctx, next->d_name.name, next->d_name.len, next->d_inode->i_ino, dt_type(next->d_inode))) return 0; spin_lock(&dentry->d_lock); spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED); /* next is still alive */ list_move(q, p); spin_unlock(&next->d_lock); p = q; ctx->pos++; |
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} |
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spin_unlock(&dentry->d_lock); |
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return 0; } |
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EXPORT_SYMBOL(dcache_readdir); |
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ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) { return -EISDIR; } |
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EXPORT_SYMBOL(generic_read_dir); |
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const struct file_operations simple_dir_operations = { |
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.open = dcache_dir_open, .release = dcache_dir_close, .llseek = dcache_dir_lseek, .read = generic_read_dir, |
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.iterate = dcache_readdir, |
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.fsync = noop_fsync, |
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}; |
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EXPORT_SYMBOL(simple_dir_operations); |
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const struct inode_operations simple_dir_inode_operations = { |
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.lookup = simple_lookup, }; |
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EXPORT_SYMBOL(simple_dir_inode_operations); |
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static const struct super_operations simple_super_operations = { .statfs = simple_statfs, }; |
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/* * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that * will never be mountable) */ |
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struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, |
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const struct super_operations *ops, const struct dentry_operations *dops, unsigned long magic) |
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{ |
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struct super_block *s; |
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struct dentry *dentry; struct inode *root; |
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struct qstr d_name = QSTR_INIT(name, strlen(name)); |
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s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); |
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if (IS_ERR(s)) |
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return ERR_CAST(s); |
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s->s_maxbytes = MAX_LFS_FILESIZE; |
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s->s_blocksize = PAGE_SIZE; s->s_blocksize_bits = PAGE_SHIFT; |
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s->s_magic = magic; |
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s->s_op = ops ? ops : &simple_super_operations; |
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s->s_time_gran = 1; root = new_inode(s); if (!root) goto Enomem; |
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/* * since this is the first inode, make it number 1. New inodes created * after this must take care not to collide with it (by passing * max_reserved of 1 to iunique). */ root->i_ino = 1; |
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root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
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root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
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dentry = __d_alloc(s, &d_name); |
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if (!dentry) { iput(root); goto Enomem; } |
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d_instantiate(dentry, root); s->s_root = dentry; |
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s->s_d_op = dops; |
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s->s_flags |= MS_ACTIVE; |
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return dget(s->s_root); |
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Enomem: |
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deactivate_locked_super(s); |
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return ERR_PTR(-ENOMEM); |
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} |
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EXPORT_SYMBOL(mount_pseudo); |
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int simple_open(struct inode *inode, struct file *file) { if (inode->i_private) file->private_data = inode->i_private; return 0; } |
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EXPORT_SYMBOL(simple_open); |
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int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) { struct inode *inode = old_dentry->d_inode; inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
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inc_nlink(inode); |
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ihold(inode); |
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dget(dentry); d_instantiate(dentry, inode); return 0; } |
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EXPORT_SYMBOL(simple_link); |
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int simple_empty(struct dentry *dentry) { struct dentry *child; int ret = 0; |
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spin_lock(&dentry->d_lock); |
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list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) { spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); if (simple_positive(child)) { spin_unlock(&child->d_lock); |
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goto out; |
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} spin_unlock(&child->d_lock); } |
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ret = 1; out: |
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spin_unlock(&dentry->d_lock); |
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return ret; } |
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EXPORT_SYMBOL(simple_empty); |
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int simple_unlink(struct inode *dir, struct dentry *dentry) { struct inode *inode = dentry->d_inode; inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
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drop_nlink(inode); |
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dput(dentry); return 0; } |
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EXPORT_SYMBOL(simple_unlink); |
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int simple_rmdir(struct inode *dir, struct dentry *dentry) { if (!simple_empty(dentry)) return -ENOTEMPTY; |
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drop_nlink(dentry->d_inode); |
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simple_unlink(dir, dentry); |
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drop_nlink(dir); |
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return 0; } |
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EXPORT_SYMBOL(simple_rmdir); |
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int simple_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) { struct inode *inode = old_dentry->d_inode; int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); if (!simple_empty(new_dentry)) return -ENOTEMPTY; if (new_dentry->d_inode) { simple_unlink(new_dir, new_dentry); |
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if (they_are_dirs) { drop_nlink(new_dentry->d_inode); |
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drop_nlink(old_dir); |
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} |
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} else if (they_are_dirs) { |
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drop_nlink(old_dir); |
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inc_nlink(new_dir); |
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} old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; return 0; } |
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EXPORT_SYMBOL(simple_rename); |
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/** |
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* simple_setattr - setattr for simple filesystem |
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* @dentry: dentry * @iattr: iattr structure * * Returns 0 on success, -error on failure. * |
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* simple_setattr is a simple ->setattr implementation without a proper * implementation of size changes. * * It can either be used for in-memory filesystems or special files * on simple regular filesystems. Anything that needs to change on-disk * or wire state on size changes needs its own setattr method. |
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*/ int simple_setattr(struct dentry *dentry, struct iattr *iattr) { struct inode *inode = dentry->d_inode; int error; error = inode_change_ok(inode, iattr); if (error) return error; |
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if (iattr->ia_valid & ATTR_SIZE) truncate_setsize(inode, iattr->ia_size); |
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setattr_copy(inode, iattr); |
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mark_inode_dirty(inode); return 0; |
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} EXPORT_SYMBOL(simple_setattr); |
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int simple_readpage(struct file *file, struct page *page) { |
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clear_highpage(page); |
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flush_dcache_page(page); SetPageUptodate(page); |
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unlock_page(page); return 0; } |
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EXPORT_SYMBOL(simple_readpage); |
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int simple_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { struct page *page; pgoff_t index; |
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index = pos >> PAGE_CACHE_SHIFT; |
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page = grab_cache_page_write_begin(mapping, index, flags); |
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if (!page) return -ENOMEM; *pagep = page; |
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if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { unsigned from = pos & (PAGE_CACHE_SIZE - 1); zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); } return 0; |
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} |
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EXPORT_SYMBOL(simple_write_begin); |
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/** * simple_write_end - .write_end helper for non-block-device FSes * @available: See .write_end of address_space_operations * @file: " * @mapping: " * @pos: " * @len: " * @copied: " * @page: " * @fsdata: " * * simple_write_end does the minimum needed for updating a page after writing is * done. It has the same API signature as the .write_end of * address_space_operations vector. So it can just be set onto .write_end for * FSes that don't need any other processing. i_mutex is assumed to be held. * Block based filesystems should use generic_write_end(). * NOTE: Even though i_size might get updated by this function, mark_inode_dirty * is not called, so a filesystem that actually does store data in .write_inode * should extend on what's done here with a call to mark_inode_dirty() in the * case that i_size has changed. */ |
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int simple_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { |
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struct inode *inode = page->mapping->host; loff_t last_pos = pos + copied; |
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/* zero the stale part of the page if we did a short copy */ if (copied < len) { |
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unsigned from = pos & (PAGE_CACHE_SIZE - 1); zero_user(page, from + copied, len - copied); |
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} |
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if (!PageUptodate(page)) SetPageUptodate(page); /* * No need to use i_size_read() here, the i_size * cannot change under us because we hold the i_mutex. */ if (last_pos > inode->i_size) i_size_write(inode, last_pos); |
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set_page_dirty(page); |
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unlock_page(page); page_cache_release(page); return copied; } |
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EXPORT_SYMBOL(simple_write_end); |
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/* * the inodes created here are not hashed. If you use iunique to generate * unique inode values later for this filesystem, then you must take care * to pass it an appropriate max_reserved value to avoid collisions. */ |
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int simple_fill_super(struct super_block *s, unsigned long magic, struct tree_descr *files) |
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{ |
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struct inode *inode; struct dentry *root; struct dentry *dentry; int i; s->s_blocksize = PAGE_CACHE_SIZE; s->s_blocksize_bits = PAGE_CACHE_SHIFT; s->s_magic = magic; |
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s->s_op = &simple_super_operations; |
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s->s_time_gran = 1; inode = new_inode(s); if (!inode) return -ENOMEM; |
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/* * because the root inode is 1, the files array must not contain an * entry at index 1 */ inode->i_ino = 1; |
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inode->i_mode = S_IFDIR | 0755; |
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; |
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set_nlink(inode, 2); |
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|
490 491 |
root = d_make_root(inode); if (!root) |
1da177e4c
|
492 |
return -ENOMEM; |
1da177e4c
|
493 494 495 |
for (i = 0; !files->name || files->name[0]; i++, files++) { if (!files->name) continue; |
1a1c9bb43
|
496 497 498 499 500 501 502 |
/* warn if it tries to conflict with the root inode */ if (unlikely(i == 1)) printk(KERN_WARNING "%s: %s passed in a files array" "with an index of 1! ", __func__, s->s_type->name); |
1da177e4c
|
503 504 505 506 |
dentry = d_alloc_name(root, files->name); if (!dentry) goto out; inode = new_inode(s); |
32096ea1a
|
507 508 |
if (!inode) { dput(dentry); |
1da177e4c
|
509 |
goto out; |
32096ea1a
|
510 |
} |
1da177e4c
|
511 |
inode->i_mode = S_IFREG | files->mode; |
1da177e4c
|
512 513 514 515 516 517 518 519 520 |
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_fop = files->ops; inode->i_ino = i; d_add(dentry, inode); } s->s_root = root; return 0; out: d_genocide(root); |
640946f20
|
521 |
shrink_dcache_parent(root); |
1da177e4c
|
522 523 524 |
dput(root); return -ENOMEM; } |
12f388722
|
525 |
EXPORT_SYMBOL(simple_fill_super); |
1da177e4c
|
526 527 |
static DEFINE_SPINLOCK(pin_fs_lock); |
1f5ce9e93
|
528 |
int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4c
|
529 530 531 532 533 |
{ struct vfsmount *mnt = NULL; spin_lock(&pin_fs_lock); if (unlikely(!*mount)) { spin_unlock(&pin_fs_lock); |
2452992aa
|
534 |
mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); |
1da177e4c
|
535 536 537 538 539 540 541 542 543 544 545 546 |
if (IS_ERR(mnt)) return PTR_ERR(mnt); spin_lock(&pin_fs_lock); if (!*mount) *mount = mnt; } mntget(*mount); ++*count; spin_unlock(&pin_fs_lock); mntput(mnt); return 0; } |
12f388722
|
547 |
EXPORT_SYMBOL(simple_pin_fs); |
1da177e4c
|
548 549 550 551 552 553 554 555 556 557 558 |
void simple_release_fs(struct vfsmount **mount, int *count) { struct vfsmount *mnt; spin_lock(&pin_fs_lock); mnt = *mount; if (!--*count) *mount = NULL; spin_unlock(&pin_fs_lock); mntput(mnt); } |
12f388722
|
559 |
EXPORT_SYMBOL(simple_release_fs); |
1da177e4c
|
560 |
|
6d1029b56
|
561 562 563 564 565 566 567 568 569 570 571 572 573 574 |
/** * simple_read_from_buffer - copy data from the buffer to user space * @to: the user space buffer to read to * @count: the maximum number of bytes to read * @ppos: the current position in the buffer * @from: the buffer to read from * @available: the size of the buffer * * The simple_read_from_buffer() function reads up to @count bytes from the * buffer @from at offset @ppos into the user space address starting at @to. * * On success, the number of bytes read is returned and the offset @ppos is * advanced by this number, or negative value is returned on error. **/ |
1da177e4c
|
575 576 577 578 |
ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, const void *from, size_t available) { loff_t pos = *ppos; |
14be27460
|
579 |
size_t ret; |
1da177e4c
|
580 581 |
if (pos < 0) return -EINVAL; |
14be27460
|
582 |
if (pos >= available || !count) |
1da177e4c
|
583 584 585 |
return 0; if (count > available - pos) count = available - pos; |
14be27460
|
586 587 |
ret = copy_to_user(to, from + pos, count); if (ret == count) |
1da177e4c
|
588 |
return -EFAULT; |
14be27460
|
589 |
count -= ret; |
1da177e4c
|
590 591 592 |
*ppos = pos + count; return count; } |
12f388722
|
593 |
EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4c
|
594 |
|
6d1029b56
|
595 |
/** |
6a727b43b
|
596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 |
* simple_write_to_buffer - copy data from user space to the buffer * @to: the buffer to write to * @available: the size of the buffer * @ppos: the current position in the buffer * @from: the user space buffer to read from * @count: the maximum number of bytes to read * * The simple_write_to_buffer() function reads up to @count bytes from the user * space address starting at @from into the buffer @to at offset @ppos. * * On success, the number of bytes written is returned and the offset @ppos is * advanced by this number, or negative value is returned on error. **/ ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, const void __user *from, size_t count) { loff_t pos = *ppos; size_t res; if (pos < 0) return -EINVAL; if (pos >= available || !count) return 0; if (count > available - pos) count = available - pos; res = copy_from_user(to + pos, from, count); if (res == count) return -EFAULT; count -= res; *ppos = pos + count; return count; } |
12f388722
|
628 |
EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43b
|
629 630 |
/** |
6d1029b56
|
631 632 633 634 635 636 637 638 639 640 641 642 643 |
* memory_read_from_buffer - copy data from the buffer * @to: the kernel space buffer to read to * @count: the maximum number of bytes to read * @ppos: the current position in the buffer * @from: the buffer to read from * @available: the size of the buffer * * The memory_read_from_buffer() function reads up to @count bytes from the * buffer @from at offset @ppos into the kernel space address starting at @to. * * On success, the number of bytes read is returned and the offset @ppos is * advanced by this number, or negative value is returned on error. **/ |
93b071139
|
644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 |
ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, const void *from, size_t available) { loff_t pos = *ppos; if (pos < 0) return -EINVAL; if (pos >= available) return 0; if (count > available - pos) count = available - pos; memcpy(to, from + pos, count); *ppos = pos + count; return count; } |
12f388722
|
660 |
EXPORT_SYMBOL(memory_read_from_buffer); |
93b071139
|
661 |
|
1da177e4c
|
662 663 664 665 666 667 |
/* * Transaction based IO. * The file expects a single write which triggers the transaction, and then * possibly a read which collects the result - which is stored in a * file-local buffer. */ |
76791ab2d
|
668 669 670 671 672 673 674 675 676 677 678 679 680 681 |
void simple_transaction_set(struct file *file, size_t n) { struct simple_transaction_argresp *ar = file->private_data; BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); /* * The barrier ensures that ar->size will really remain zero until * ar->data is ready for reading. */ smp_mb(); ar->size = n; } |
12f388722
|
682 |
EXPORT_SYMBOL(simple_transaction_set); |
76791ab2d
|
683 |
|
1da177e4c
|
684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 |
char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) { struct simple_transaction_argresp *ar; static DEFINE_SPINLOCK(simple_transaction_lock); if (size > SIMPLE_TRANSACTION_LIMIT - 1) return ERR_PTR(-EFBIG); ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); if (!ar) return ERR_PTR(-ENOMEM); spin_lock(&simple_transaction_lock); /* only one write allowed per open */ if (file->private_data) { spin_unlock(&simple_transaction_lock); free_page((unsigned long)ar); return ERR_PTR(-EBUSY); } file->private_data = ar; spin_unlock(&simple_transaction_lock); if (copy_from_user(ar->data, buf, size)) return ERR_PTR(-EFAULT); return ar->data; } |
12f388722
|
714 |
EXPORT_SYMBOL(simple_transaction_get); |
1da177e4c
|
715 716 717 718 719 720 721 722 723 |
ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) { struct simple_transaction_argresp *ar = file->private_data; if (!ar) return 0; return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); } |
12f388722
|
724 |
EXPORT_SYMBOL(simple_transaction_read); |
1da177e4c
|
725 726 727 728 729 730 |
int simple_transaction_release(struct inode *inode, struct file *file) { free_page((unsigned long)file->private_data); return 0; } |
12f388722
|
731 |
EXPORT_SYMBOL(simple_transaction_release); |
1da177e4c
|
732 |
|
acaefc25d
|
733 734 735 |
/* Simple attribute files */ struct simple_attr { |
8b88b0998
|
736 737 |
int (*get)(void *, u64 *); int (*set)(void *, u64); |
acaefc25d
|
738 739 740 741 742 |
char get_buf[24]; /* enough to store a u64 and " \0" */ char set_buf[24]; void *data; const char *fmt; /* format for read operation */ |
7cf34c761
|
743 |
struct mutex mutex; /* protects access to these buffers */ |
acaefc25d
|
744 745 746 747 748 |
}; /* simple_attr_open is called by an actual attribute open file operation * to set the attribute specific access operations. */ int simple_attr_open(struct inode *inode, struct file *file, |
8b88b0998
|
749 |
int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25d
|
750 751 752 753 754 755 756 757 758 759 |
const char *fmt) { struct simple_attr *attr; attr = kmalloc(sizeof(*attr), GFP_KERNEL); if (!attr) return -ENOMEM; attr->get = get; attr->set = set; |
8e18e2941
|
760 |
attr->data = inode->i_private; |
acaefc25d
|
761 |
attr->fmt = fmt; |
7cf34c761
|
762 |
mutex_init(&attr->mutex); |
acaefc25d
|
763 764 765 766 767 |
file->private_data = attr; return nonseekable_open(inode, file); } |
12f388722
|
768 |
EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25d
|
769 |
|
74bedc4d5
|
770 |
int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25d
|
771 772 773 774 |
{ kfree(file->private_data); return 0; } |
12f388722
|
775 |
EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25d
|
776 777 778 779 780 781 782 783 784 785 786 787 788 |
/* read from the buffer that is filled with the get function */ ssize_t simple_attr_read(struct file *file, char __user *buf, size_t len, loff_t *ppos) { struct simple_attr *attr; size_t size; ssize_t ret; attr = file->private_data; if (!attr->get) return -EACCES; |
9261303ab
|
789 790 791 |
ret = mutex_lock_interruptible(&attr->mutex); if (ret) return ret; |
8b88b0998
|
792 |
if (*ppos) { /* continued read */ |
acaefc25d
|
793 |
size = strlen(attr->get_buf); |
8b88b0998
|
794 795 796 797 798 |
} else { /* first read */ u64 val; ret = attr->get(attr->data, &val); if (ret) goto out; |
acaefc25d
|
799 |
size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b0998
|
800 801 |
attr->fmt, (unsigned long long)val); } |
acaefc25d
|
802 803 |
ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); |
8b88b0998
|
804 |
out: |
7cf34c761
|
805 |
mutex_unlock(&attr->mutex); |
acaefc25d
|
806 807 |
return ret; } |
12f388722
|
808 |
EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25d
|
809 810 811 812 813 814 815 816 817 818 819 |
/* interpret the buffer as a number to call the set function with */ ssize_t simple_attr_write(struct file *file, const char __user *buf, size_t len, loff_t *ppos) { struct simple_attr *attr; u64 val; size_t size; ssize_t ret; attr = file->private_data; |
acaefc25d
|
820 821 |
if (!attr->set) return -EACCES; |
9261303ab
|
822 823 824 |
ret = mutex_lock_interruptible(&attr->mutex); if (ret) return ret; |
acaefc25d
|
825 826 827 828 |
ret = -EFAULT; size = min(sizeof(attr->set_buf) - 1, len); if (copy_from_user(attr->set_buf, buf, size)) goto out; |
acaefc25d
|
829 |
attr->set_buf[size] = '\0'; |
f7b88631a
|
830 |
val = simple_strtoll(attr->set_buf, NULL, 0); |
05cc0cee6
|
831 832 833 |
ret = attr->set(attr->data, val); if (ret == 0) ret = len; /* on success, claim we got the whole input */ |
acaefc25d
|
834 |
out: |
7cf34c761
|
835 |
mutex_unlock(&attr->mutex); |
acaefc25d
|
836 837 |
return ret; } |
12f388722
|
838 |
EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25d
|
839 |
|
2596110a3
|
840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 |
/** * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation * @sb: filesystem to do the file handle conversion on * @fid: file handle to convert * @fh_len: length of the file handle in bytes * @fh_type: type of file handle * @get_inode: filesystem callback to retrieve inode * * This function decodes @fid as long as it has one of the well-known * Linux filehandle types and calls @get_inode on it to retrieve the * inode for the object specified in the file handle. */ struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len, int fh_type, struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)) { struct inode *inode = NULL; if (fh_len < 2) return NULL; switch (fh_type) { case FILEID_INO32_GEN: case FILEID_INO32_GEN_PARENT: inode = get_inode(sb, fid->i32.ino, fid->i32.gen); break; } |
4ea3ada29
|
867 |
return d_obtain_alias(inode); |
2596110a3
|
868 869 870 871 |
} EXPORT_SYMBOL_GPL(generic_fh_to_dentry); /** |
ca1868309
|
872 |
* generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a3
|
873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 |
* @sb: filesystem to do the file handle conversion on * @fid: file handle to convert * @fh_len: length of the file handle in bytes * @fh_type: type of file handle * @get_inode: filesystem callback to retrieve inode * * This function decodes @fid as long as it has one of the well-known * Linux filehandle types and calls @get_inode on it to retrieve the * inode for the _parent_ object specified in the file handle if it * is specified in the file handle, or NULL otherwise. */ struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len, int fh_type, struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen)) { struct inode *inode = NULL; if (fh_len <= 2) return NULL; switch (fh_type) { case FILEID_INO32_GEN_PARENT: inode = get_inode(sb, fid->i32.parent_ino, (fh_len > 3 ? fid->i32.parent_gen : 0)); break; } |
4ea3ada29
|
899 |
return d_obtain_alias(inode); |
2596110a3
|
900 901 |
} EXPORT_SYMBOL_GPL(generic_fh_to_parent); |
1b061d924
|
902 903 904 905 906 907 908 909 910 |
/** * generic_file_fsync - generic fsync implementation for simple filesystems * @file: file to synchronize * @datasync: only synchronize essential metadata if true * * This is a generic implementation of the fsync method for simple * filesystems which track all non-inode metadata in the buffers list * hanging off the address_space structure. */ |
02c24a821
|
911 912 |
int generic_file_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
d5aacad54
|
913 |
{ |
7ea808591
|
914 |
struct inode *inode = file->f_mapping->host; |
d5aacad54
|
915 916 |
int err; int ret; |
02c24a821
|
917 918 919 920 921 |
err = filemap_write_and_wait_range(inode->i_mapping, start, end); if (err) return err; mutex_lock(&inode->i_mutex); |
d5aacad54
|
922 923 |
ret = sync_mapping_buffers(inode->i_mapping); if (!(inode->i_state & I_DIRTY)) |
02c24a821
|
924 |
goto out; |
d5aacad54
|
925 |
if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a821
|
926 |
goto out; |
d5aacad54
|
927 |
|
c37650161
|
928 |
err = sync_inode_metadata(inode, 1); |
d5aacad54
|
929 930 |
if (ret == 0) ret = err; |
02c24a821
|
931 932 |
out: mutex_unlock(&inode->i_mutex); |
d5aacad54
|
933 934 |
return ret; } |
1b061d924
|
935 |
EXPORT_SYMBOL(generic_file_fsync); |
30ca22c70
|
936 937 938 939 940 941 942 943 944 945 946 947 |
/** * generic_check_addressable - Check addressability of file system * @blocksize_bits: log of file system block size * @num_blocks: number of blocks in file system * * Determine whether a file system with @num_blocks blocks (and a * block size of 2**@blocksize_bits) is addressable by the sector_t * and page cache of the system. Return 0 if so and -EFBIG otherwise. */ int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) { u64 last_fs_block = num_blocks - 1; |
a33f13efe
|
948 949 |
u64 last_fs_page = last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits); |
30ca22c70
|
950 951 952 953 954 955 |
if (unlikely(num_blocks == 0)) return 0; if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT)) return -EINVAL; |
a33f13efe
|
956 957 |
if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || (last_fs_page > (pgoff_t)(~0ULL))) { |
30ca22c70
|
958 959 960 961 962 |
return -EFBIG; } return 0; } EXPORT_SYMBOL(generic_check_addressable); |
1b061d924
|
963 964 965 |
/* * No-op implementation of ->fsync for in-memory filesystems. */ |
02c24a821
|
966 |
int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d924
|
967 968 969 |
{ return 0; } |
1b061d924
|
970 |
EXPORT_SYMBOL(noop_fsync); |
87dc800be
|
971 972 973 974 975 976 977 978 979 |
void kfree_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) { char *s = nd_get_link(nd); if (!IS_ERR(s)) kfree(s); } EXPORT_SYMBOL(kfree_put_link); |
6987843ff
|
980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 |
/* * nop .set_page_dirty method so that people can use .page_mkwrite on * anon inodes. */ static int anon_set_page_dirty(struct page *page) { return 0; }; /* * A single inode exists for all anon_inode files. Contrary to pipes, * anon_inode inodes have no associated per-instance data, so we need * only allocate one of them. */ struct inode *alloc_anon_inode(struct super_block *s) { static const struct address_space_operations anon_aops = { .set_page_dirty = anon_set_page_dirty, }; struct inode *inode = new_inode_pseudo(s); if (!inode) return ERR_PTR(-ENOMEM); inode->i_ino = get_next_ino(); inode->i_mapping->a_ops = &anon_aops; /* * Mark the inode dirty from the very beginning, * that way it will never be moved to the dirty * list because mark_inode_dirty() will think * that it already _is_ on the dirty list. */ inode->i_state = I_DIRTY; inode->i_mode = S_IRUSR | S_IWUSR; inode->i_uid = current_fsuid(); inode->i_gid = current_fsgid(); inode->i_flags |= S_PRIVATE; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; return inode; } EXPORT_SYMBOL(alloc_anon_inode); |