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fs/libfs.c
30.3 KB
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/* * fs/libfs.c * Library for filesystems writers. */ |
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#include <linux/blkdev.h> |
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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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|
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#include <asm/uaccess.h> |
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#include "internal.h" |
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int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { |
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struct inode *inode = d_inode(dentry); |
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generic_fillattr(inode, stat); |
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stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
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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_SIZE; |
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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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file->private_data = d_alloc_cursor(file->f_path.dentry); |
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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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/* parent is locked at least shared */ static struct dentry *next_positive(struct dentry *parent, struct list_head *from, int count) { |
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unsigned *seq = &parent->d_inode->i_dir_seq, n; struct dentry *res; |
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struct list_head *p; |
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bool skipped; int i; retry: i = count; skipped = false; n = smp_load_acquire(seq) & ~1; res = NULL; rcu_read_lock(); |
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for (p = from->next; p != &parent->d_subdirs; p = p->next) { struct dentry *d = list_entry(p, struct dentry, d_child); |
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if (!simple_positive(d)) { skipped = true; } else if (!--i) { |
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res = d; break; } } |
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rcu_read_unlock(); if (skipped) { smp_rmb(); if (unlikely(*seq != n)) goto retry; } |
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return res; } static void move_cursor(struct dentry *cursor, struct list_head *after) { struct dentry *parent = cursor->d_parent; |
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unsigned n, *seq = &parent->d_inode->i_dir_seq; |
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spin_lock(&parent->d_lock); |
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for (;;) { n = *seq; if (!(n & 1) && cmpxchg(seq, n, n + 1) == n) break; cpu_relax(); } |
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__list_del(cursor->d_child.prev, cursor->d_child.next); if (after) list_add(&cursor->d_child, after); else list_add_tail(&cursor->d_child, &parent->d_subdirs); |
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smp_store_release(seq, n + 2); |
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spin_unlock(&parent->d_lock); } |
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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; |
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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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return -EINVAL; } if (offset != file->f_pos) { file->f_pos = offset; if (file->f_pos >= 2) { |
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struct dentry *cursor = file->private_data; |
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struct dentry *to; |
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loff_t n = file->f_pos - 2; |
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inode_lock_shared(dentry->d_inode); |
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to = next_positive(dentry, &dentry->d_subdirs, n); move_cursor(cursor, to ? &to->d_child : NULL); |
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inode_unlock_shared(dentry->d_inode); |
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} } |
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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 = &cursor->d_child; struct dentry *next; bool moved = false; |
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if (!dir_emit_dots(file, ctx)) return 0; |
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if (ctx->pos == 2) p = &dentry->d_subdirs; while ((next = next_positive(dentry, p, 1)) != NULL) { |
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if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
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d_inode(next)->i_ino, dt_type(d_inode(next)))) |
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break; moved = true; p = &next->d_child; |
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ctx->pos++; |
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} |
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if (moved) move_cursor(cursor, p); |
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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_shared = 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_xattr(struct file_system_type *fs_type, char *name, const struct super_operations *ops, const struct xattr_handler **xattr, |
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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_xattr = xattr; |
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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(root); |
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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_xattr); |
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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) { |
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struct inode *inode = d_inode(old_dentry); |
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inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
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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_child) { |
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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) { |
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struct inode *inode = d_inode(dentry); |
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inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
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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(d_inode(dentry)); |
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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, |
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struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) |
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{ |
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struct inode *inode = d_inode(old_dentry); |
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int they_are_dirs = d_is_dir(old_dentry); |
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if (flags & ~RENAME_NOREPLACE) return -EINVAL; |
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if (!simple_empty(new_dentry)) return -ENOTEMPTY; |
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if (d_really_is_positive(new_dentry)) { |
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simple_unlink(new_dir, new_dentry); |
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if (they_are_dirs) { |
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drop_nlink(d_inode(new_dentry)); |
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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 = |
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new_dir->i_mtime = inode->i_ctime = current_time(old_dir); |
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return 0; } |
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EXPORT_SYMBOL(simple_rename); |
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|
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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) { |
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struct inode *inode = d_inode(dentry); |
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int error; |
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error = setattr_prepare(dentry, iattr); |
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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_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_SIZE)) { unsigned from = pos & (PAGE_SIZE - 1); |
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zero_user_segments(page, 0, from, from + len, PAGE_SIZE); |
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} 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; |
afddba49d
|
460 461 462 |
/* zero the stale part of the page if we did a short copy */ if (copied < len) { |
09cbfeaf1
|
463 |
unsigned from = pos & (PAGE_SIZE - 1); |
ad2a722f1
|
464 465 |
zero_user(page, from + copied, len - copied); |
afddba49d
|
466 |
} |
ad2a722f1
|
467 468 469 470 471 472 473 474 |
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); |
afddba49d
|
475 |
|
ad2a722f1
|
476 |
set_page_dirty(page); |
afddba49d
|
477 |
unlock_page(page); |
09cbfeaf1
|
478 |
put_page(page); |
afddba49d
|
479 480 481 |
return copied; } |
12f388722
|
482 |
EXPORT_SYMBOL(simple_write_end); |
afddba49d
|
483 |
|
1a1c9bb43
|
484 485 486 487 488 |
/* * 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. */ |
7d683a099
|
489 490 |
int simple_fill_super(struct super_block *s, unsigned long magic, struct tree_descr *files) |
1da177e4c
|
491 |
{ |
1da177e4c
|
492 493 494 495 |
struct inode *inode; struct dentry *root; struct dentry *dentry; int i; |
09cbfeaf1
|
496 497 |
s->s_blocksize = PAGE_SIZE; s->s_blocksize_bits = PAGE_SHIFT; |
1da177e4c
|
498 |
s->s_magic = magic; |
759b9775c
|
499 |
s->s_op = &simple_super_operations; |
1da177e4c
|
500 501 502 503 504 |
s->s_time_gran = 1; inode = new_inode(s); if (!inode) return -ENOMEM; |
1a1c9bb43
|
505 506 507 508 509 |
/* * because the root inode is 1, the files array must not contain an * entry at index 1 */ inode->i_ino = 1; |
1da177e4c
|
510 |
inode->i_mode = S_IFDIR | 0755; |
078cd8279
|
511 |
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
1da177e4c
|
512 513 |
inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; |
bfe868486
|
514 |
set_nlink(inode, 2); |
48fde701a
|
515 516 |
root = d_make_root(inode); if (!root) |
1da177e4c
|
517 |
return -ENOMEM; |
1da177e4c
|
518 519 520 |
for (i = 0; !files->name || files->name[0]; i++, files++) { if (!files->name) continue; |
1a1c9bb43
|
521 522 523 524 525 526 527 |
/* 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
|
528 529 530 531 |
dentry = d_alloc_name(root, files->name); if (!dentry) goto out; inode = new_inode(s); |
32096ea1a
|
532 533 |
if (!inode) { dput(dentry); |
1da177e4c
|
534 |
goto out; |
32096ea1a
|
535 |
} |
1da177e4c
|
536 |
inode->i_mode = S_IFREG | files->mode; |
078cd8279
|
537 |
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
1da177e4c
|
538 539 540 541 542 543 544 545 |
inode->i_fop = files->ops; inode->i_ino = i; d_add(dentry, inode); } s->s_root = root; return 0; out: d_genocide(root); |
640946f20
|
546 |
shrink_dcache_parent(root); |
1da177e4c
|
547 548 549 |
dput(root); return -ENOMEM; } |
12f388722
|
550 |
EXPORT_SYMBOL(simple_fill_super); |
1da177e4c
|
551 552 |
static DEFINE_SPINLOCK(pin_fs_lock); |
1f5ce9e93
|
553 |
int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4c
|
554 555 556 557 558 |
{ struct vfsmount *mnt = NULL; spin_lock(&pin_fs_lock); if (unlikely(!*mount)) { spin_unlock(&pin_fs_lock); |
2452992aa
|
559 |
mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); |
1da177e4c
|
560 561 562 563 564 565 566 567 568 569 570 571 |
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
|
572 |
EXPORT_SYMBOL(simple_pin_fs); |
1da177e4c
|
573 574 575 576 577 578 579 580 581 582 583 |
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
|
584 |
EXPORT_SYMBOL(simple_release_fs); |
1da177e4c
|
585 |
|
6d1029b56
|
586 587 588 589 590 591 592 593 594 595 596 597 598 599 |
/** * 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
|
600 601 602 603 |
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
|
604 |
size_t ret; |
1da177e4c
|
605 606 |
if (pos < 0) return -EINVAL; |
14be27460
|
607 |
if (pos >= available || !count) |
1da177e4c
|
608 609 610 |
return 0; if (count > available - pos) count = available - pos; |
14be27460
|
611 612 |
ret = copy_to_user(to, from + pos, count); if (ret == count) |
1da177e4c
|
613 |
return -EFAULT; |
14be27460
|
614 |
count -= ret; |
1da177e4c
|
615 616 617 |
*ppos = pos + count; return count; } |
12f388722
|
618 |
EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4c
|
619 |
|
6d1029b56
|
620 |
/** |
6a727b43b
|
621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 |
* 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
|
653 |
EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43b
|
654 655 |
/** |
6d1029b56
|
656 657 658 659 660 661 662 663 664 665 666 667 668 |
* 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
|
669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 |
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
|
685 |
EXPORT_SYMBOL(memory_read_from_buffer); |
93b071139
|
686 |
|
1da177e4c
|
687 688 689 690 691 692 |
/* * 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
|
693 694 695 696 697 698 699 700 701 702 703 704 705 706 |
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
|
707 |
EXPORT_SYMBOL(simple_transaction_set); |
76791ab2d
|
708 |
|
1da177e4c
|
709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 |
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
|
739 |
EXPORT_SYMBOL(simple_transaction_get); |
1da177e4c
|
740 741 742 743 744 745 746 747 748 |
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
|
749 |
EXPORT_SYMBOL(simple_transaction_read); |
1da177e4c
|
750 751 752 753 754 755 |
int simple_transaction_release(struct inode *inode, struct file *file) { free_page((unsigned long)file->private_data); return 0; } |
12f388722
|
756 |
EXPORT_SYMBOL(simple_transaction_release); |
1da177e4c
|
757 |
|
acaefc25d
|
758 759 760 |
/* Simple attribute files */ struct simple_attr { |
8b88b0998
|
761 762 |
int (*get)(void *, u64 *); int (*set)(void *, u64); |
acaefc25d
|
763 764 765 766 767 |
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
|
768 |
struct mutex mutex; /* protects access to these buffers */ |
acaefc25d
|
769 770 771 772 773 |
}; /* 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
|
774 |
int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25d
|
775 776 777 778 779 780 781 782 783 784 |
const char *fmt) { struct simple_attr *attr; attr = kmalloc(sizeof(*attr), GFP_KERNEL); if (!attr) return -ENOMEM; attr->get = get; attr->set = set; |
8e18e2941
|
785 |
attr->data = inode->i_private; |
acaefc25d
|
786 |
attr->fmt = fmt; |
7cf34c761
|
787 |
mutex_init(&attr->mutex); |
acaefc25d
|
788 789 790 791 792 |
file->private_data = attr; return nonseekable_open(inode, file); } |
12f388722
|
793 |
EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25d
|
794 |
|
74bedc4d5
|
795 |
int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25d
|
796 797 798 799 |
{ kfree(file->private_data); return 0; } |
12f388722
|
800 |
EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25d
|
801 802 803 804 805 806 807 808 809 810 811 812 813 |
/* 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
|
814 815 816 |
ret = mutex_lock_interruptible(&attr->mutex); if (ret) return ret; |
8b88b0998
|
817 |
if (*ppos) { /* continued read */ |
acaefc25d
|
818 |
size = strlen(attr->get_buf); |
8b88b0998
|
819 820 821 822 823 |
} else { /* first read */ u64 val; ret = attr->get(attr->data, &val); if (ret) goto out; |
acaefc25d
|
824 |
size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b0998
|
825 826 |
attr->fmt, (unsigned long long)val); } |
acaefc25d
|
827 828 |
ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); |
8b88b0998
|
829 |
out: |
7cf34c761
|
830 |
mutex_unlock(&attr->mutex); |
acaefc25d
|
831 832 |
return ret; } |
12f388722
|
833 |
EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25d
|
834 835 836 837 838 839 840 841 842 843 844 |
/* 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
|
845 846 |
if (!attr->set) return -EACCES; |
9261303ab
|
847 848 849 |
ret = mutex_lock_interruptible(&attr->mutex); if (ret) return ret; |
acaefc25d
|
850 851 852 853 |
ret = -EFAULT; size = min(sizeof(attr->set_buf) - 1, len); if (copy_from_user(attr->set_buf, buf, size)) goto out; |
acaefc25d
|
854 |
attr->set_buf[size] = '\0'; |
f7b88631a
|
855 |
val = simple_strtoll(attr->set_buf, NULL, 0); |
05cc0cee6
|
856 857 858 |
ret = attr->set(attr->data, val); if (ret == 0) ret = len; /* on success, claim we got the whole input */ |
acaefc25d
|
859 |
out: |
7cf34c761
|
860 |
mutex_unlock(&attr->mutex); |
acaefc25d
|
861 862 |
return ret; } |
12f388722
|
863 |
EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25d
|
864 |
|
2596110a3
|
865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 |
/** * 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
|
892 |
return d_obtain_alias(inode); |
2596110a3
|
893 894 895 896 |
} EXPORT_SYMBOL_GPL(generic_fh_to_dentry); /** |
ca1868309
|
897 |
* generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a3
|
898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 |
* @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
|
924 |
return d_obtain_alias(inode); |
2596110a3
|
925 926 |
} EXPORT_SYMBOL_GPL(generic_fh_to_parent); |
1b061d924
|
927 |
/** |
ac13a829f
|
928 929 |
* __generic_file_fsync - generic fsync implementation for simple filesystems * |
1b061d924
|
930 |
* @file: file to synchronize |
ac13a829f
|
931 932 |
* @start: start offset in bytes * @end: end offset in bytes (inclusive) |
1b061d924
|
933 934 935 936 937 938 |
* @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. */ |
ac13a829f
|
939 940 |
int __generic_file_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
d5aacad54
|
941 |
{ |
7ea808591
|
942 |
struct inode *inode = file->f_mapping->host; |
d5aacad54
|
943 944 |
int err; int ret; |
02c24a821
|
945 946 947 |
err = filemap_write_and_wait_range(inode->i_mapping, start, end); if (err) return err; |
5955102c9
|
948 |
inode_lock(inode); |
d5aacad54
|
949 |
ret = sync_mapping_buffers(inode->i_mapping); |
0ae45f63d
|
950 |
if (!(inode->i_state & I_DIRTY_ALL)) |
02c24a821
|
951 |
goto out; |
d5aacad54
|
952 |
if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a821
|
953 |
goto out; |
d5aacad54
|
954 |
|
c37650161
|
955 |
err = sync_inode_metadata(inode, 1); |
d5aacad54
|
956 957 |
if (ret == 0) ret = err; |
ac13a829f
|
958 |
|
02c24a821
|
959 |
out: |
5955102c9
|
960 |
inode_unlock(inode); |
d5aacad54
|
961 962 |
return ret; } |
ac13a829f
|
963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 |
EXPORT_SYMBOL(__generic_file_fsync); /** * generic_file_fsync - generic fsync implementation for simple filesystems * with flush * @file: file to synchronize * @start: start offset in bytes * @end: end offset in bytes (inclusive) * @datasync: only synchronize essential metadata if true * */ int generic_file_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct inode *inode = file->f_mapping->host; int err; err = __generic_file_fsync(file, start, end, datasync); if (err) return err; return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); } |
1b061d924
|
986 |
EXPORT_SYMBOL(generic_file_fsync); |
30ca22c70
|
987 988 989 990 991 992 993 994 995 996 997 998 |
/** * 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
|
999 |
u64 last_fs_page = |
09cbfeaf1
|
1000 |
last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
30ca22c70
|
1001 1002 1003 |
if (unlikely(num_blocks == 0)) return 0; |
09cbfeaf1
|
1004 |
if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
30ca22c70
|
1005 |
return -EINVAL; |
a33f13efe
|
1006 1007 |
if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || (last_fs_page > (pgoff_t)(~0ULL))) { |
30ca22c70
|
1008 1009 1010 1011 1012 |
return -EFBIG; } return 0; } EXPORT_SYMBOL(generic_check_addressable); |
1b061d924
|
1013 1014 1015 |
/* * No-op implementation of ->fsync for in-memory filesystems. */ |
02c24a821
|
1016 |
int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d924
|
1017 1018 1019 |
{ return 0; } |
1b061d924
|
1020 |
EXPORT_SYMBOL(noop_fsync); |
87dc800be
|
1021 |
|
fceef393a
|
1022 1023 |
/* Because kfree isn't assignment-compatible with void(void*) ;-/ */ void kfree_link(void *p) |
87dc800be
|
1024 |
{ |
fceef393a
|
1025 |
kfree(p); |
87dc800be
|
1026 |
} |
fceef393a
|
1027 |
EXPORT_SYMBOL(kfree_link); |
6987843ff
|
1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 |
/* * 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; |
078cd8279
|
1067 |
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
6987843ff
|
1068 1069 1070 |
return inode; } EXPORT_SYMBOL(alloc_anon_inode); |
1c994a090
|
1071 1072 1073 1074 1075 1076 |
/** * simple_nosetlease - generic helper for prohibiting leases * @filp: file pointer * @arg: type of lease to obtain * @flp: new lease supplied for insertion |
e6f5c7893
|
1077 |
* @priv: private data for lm_setup operation |
1c994a090
|
1078 1079 1080 1081 1082 |
* * Generic helper for filesystems that do not wish to allow leases to be set. * All arguments are ignored and it just returns -EINVAL. */ int |
e6f5c7893
|
1083 1084 |
simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, void **priv) |
1c994a090
|
1085 1086 1087 1088 |
{ return -EINVAL; } EXPORT_SYMBOL(simple_nosetlease); |
61ba64fc0
|
1089 |
|
6b2553918
|
1090 |
const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
fceef393a
|
1091 |
struct delayed_call *done) |
61ba64fc0
|
1092 |
{ |
6b2553918
|
1093 |
return inode->i_link; |
61ba64fc0
|
1094 |
} |
6b2553918
|
1095 |
EXPORT_SYMBOL(simple_get_link); |
61ba64fc0
|
1096 1097 |
const struct inode_operations simple_symlink_inode_operations = { |
6b2553918
|
1098 |
.get_link = simple_get_link, |
61ba64fc0
|
1099 1100 1101 |
.readlink = generic_readlink }; EXPORT_SYMBOL(simple_symlink_inode_operations); |
fbabfd0f4
|
1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 |
/* * Operations for a permanently empty directory. */ static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { return ERR_PTR(-ENOENT); } static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct inode *inode = d_inode(dentry); generic_fillattr(inode, stat); return 0; } static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) { return -EPERM; } |
fbabfd0f4
|
1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 |
static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) { return -EOPNOTSUPP; } static const struct inode_operations empty_dir_inode_operations = { .lookup = empty_dir_lookup, .permission = generic_permission, .setattr = empty_dir_setattr, .getattr = empty_dir_getattr, |
fbabfd0f4
|
1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 |
.listxattr = empty_dir_listxattr, }; static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) { /* An empty directory has two entries . and .. at offsets 0 and 1 */ return generic_file_llseek_size(file, offset, whence, 2, 2); } static int empty_dir_readdir(struct file *file, struct dir_context *ctx) { dir_emit_dots(file, ctx); return 0; } static const struct file_operations empty_dir_operations = { .llseek = empty_dir_llseek, .read = generic_read_dir, |
c51da20c4
|
1151 |
.iterate_shared = empty_dir_readdir, |
fbabfd0f4
|
1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 |
.fsync = noop_fsync, }; void make_empty_dir_inode(struct inode *inode) { set_nlink(inode, 2); inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; inode->i_uid = GLOBAL_ROOT_UID; inode->i_gid = GLOBAL_ROOT_GID; inode->i_rdev = 0; |
4b75de861
|
1163 |
inode->i_size = 0; |
fbabfd0f4
|
1164 1165 1166 1167 |
inode->i_blkbits = PAGE_SHIFT; inode->i_blocks = 0; inode->i_op = &empty_dir_inode_operations; |
f5c244383
|
1168 |
inode->i_opflags &= ~IOP_XATTR; |
fbabfd0f4
|
1169 1170 1171 1172 1173 1174 1175 1176 |
inode->i_fop = &empty_dir_operations; } bool is_empty_dir_inode(struct inode *inode) { return (inode->i_fop == &empty_dir_operations) && (inode->i_op == &empty_dir_inode_operations); } |