X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Flibfs.c;h=dcaf972cbf1b6d81f29e17d2a1fccd259a794777;hb=f3d56144c86beb25c7d206efa66d6efba908371c;hp=74688598bcf72ebadb7f978099f9691747369d6a;hpb=4ea3ada2955e4519befa98ff55dd62d6dfbd1705;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/libfs.c b/fs/libfs.c index 7468859..dcaf972 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -5,10 +5,14 @@ #include #include +#include #include #include +#include #include #include +#include +#include #include @@ -44,7 +48,7 @@ static int simple_delete_dentry(struct dentry *dentry) */ struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { - static struct dentry_operations simple_dentry_operations = { + static const struct dentry_operations simple_dentry_operations = { .d_delete = simple_delete_dentry, }; @@ -55,11 +59,6 @@ struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct na return NULL; } -int simple_sync_file(struct file * file, struct dentry *dentry, int datasync) -{ - return 0; -} - int dcache_dir_open(struct inode *inode, struct file *file) { static struct qstr cursor_name = {.len = 1, .name = "."}; @@ -187,7 +186,7 @@ const struct file_operations simple_dir_operations = { .llseek = dcache_dir_lseek, .read = generic_read_dir, .readdir = dcache_readdir, - .fsync = simple_sync_file, + .fsync = noop_fsync, }; const struct inode_operations simple_dir_inode_operations = { @@ -215,7 +214,7 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name, return PTR_ERR(s); s->s_flags = MS_NOUSER; - s->s_maxbytes = ~0ULL; + s->s_maxbytes = MAX_LFS_FILESIZE; s->s_blocksize = PAGE_SIZE; s->s_blocksize_bits = PAGE_SHIFT; s->s_magic = magic; @@ -231,7 +230,6 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name, */ root->i_ino = 1; root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; - root->i_uid = root->i_gid = 0; root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; dentry = d_alloc(NULL, &d_name); if (!dentry) { @@ -243,11 +241,11 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name, d_instantiate(dentry, root); s->s_root = dentry; s->s_flags |= MS_ACTIVE; - return simple_set_mnt(mnt, s); + simple_set_mnt(mnt, s); + return 0; Enomem: - up_write(&s->s_umount); - deactivate_super(s); + deactivate_locked_super(s); return -ENOMEM; } @@ -328,6 +326,81 @@ int simple_rename(struct inode *old_dir, struct dentry *old_dentry, return 0; } +/** + * simple_setsize - handle core mm and vfs requirements for file size change + * @inode: inode + * @newsize: new file size + * + * Returns 0 on success, -error on failure. + * + * simple_setsize must be called with inode_mutex held. + * + * simple_setsize will check that the requested new size is OK (see + * inode_newsize_ok), and then will perform the necessary i_size update + * and pagecache truncation (if necessary). It will be typically be called + * from the filesystem's setattr function when ATTR_SIZE is passed in. + * + * The inode itself must have correct permissions and attributes to allow + * i_size to be changed, this function then just checks that the new size + * requested is valid. + * + * In the case of simple in-memory filesystems with inodes stored solely + * in the inode cache, and file data in the pagecache, nothing more needs + * to be done to satisfy a truncate request. Filesystems with on-disk + * blocks for example will need to free them in the case of truncate, in + * that case it may be easier not to use simple_setsize (but each of its + * components will likely be required at some point to update pagecache + * and inode etc). + */ +int simple_setsize(struct inode *inode, loff_t newsize) +{ + loff_t oldsize; + int error; + + error = inode_newsize_ok(inode, newsize); + if (error) + return error; + + oldsize = inode->i_size; + i_size_write(inode, newsize); + truncate_pagecache(inode, oldsize, newsize); + + return error; +} +EXPORT_SYMBOL(simple_setsize); + +/** + * simple_setattr - setattr for simple in-memory filesystem + * @dentry: dentry + * @iattr: iattr structure + * + * Returns 0 on success, -error on failure. + * + * simple_setattr implements setattr for an in-memory filesystem which + * does not store its own file data or metadata (eg. uses the page cache + * and inode cache as its data store). + */ +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; + + if (iattr->ia_valid & ATTR_SIZE) { + error = simple_setsize(inode, iattr->ia_size); + if (error) + return error; + } + + generic_setattr(inode, iattr); + + return error; +} +EXPORT_SYMBOL(simple_setattr); + int simple_readpage(struct file *file, struct page *page) { clear_highpage(page); @@ -337,72 +410,74 @@ int simple_readpage(struct file *file, struct page *page) return 0; } -int simple_prepare_write(struct file *file, struct page *page, - unsigned from, unsigned to) -{ - if (!PageUptodate(page)) { - if (to - from != PAGE_CACHE_SIZE) - zero_user_segments(page, - 0, from, - to, PAGE_CACHE_SIZE); - } - return 0; -} - 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; - unsigned from; index = pos >> PAGE_CACHE_SHIFT; - from = pos & (PAGE_CACHE_SIZE - 1); - page = __grab_cache_page(mapping, index); + page = grab_cache_page_write_begin(mapping, index, flags); if (!page) return -ENOMEM; *pagep = page; - return simple_prepare_write(file, page, from, from+len); -} - -static int simple_commit_write(struct file *file, struct page *page, - unsigned from, unsigned to) -{ - struct inode *inode = page->mapping->host; - loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; + if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { + unsigned from = pos & (PAGE_CACHE_SIZE - 1); - 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 (pos > inode->i_size) - i_size_write(inode, pos); - set_page_dirty(page); + zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); + } return 0; } +/** + * 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. + */ int simple_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { - unsigned from = pos & (PAGE_CACHE_SIZE - 1); + struct inode *inode = page->mapping->host; + loff_t last_pos = pos + copied; /* zero the stale part of the page if we did a short copy */ if (copied < len) { - void *kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + from + copied, 0, len - copied); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + unsigned from = pos & (PAGE_CACHE_SIZE - 1); + + zero_user(page, from + copied, len - copied); } - simple_commit_write(file, page, from, from+copied); + 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); + set_page_dirty(page); unlock_page(page); page_cache_release(page); @@ -414,7 +489,8 @@ int simple_write_end(struct file *file, struct address_space *mapping, * unique inode values later for this filesystem, then you must take care * to pass it an appropriate max_reserved value to avoid collisions. */ -int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files) +int simple_fill_super(struct super_block *s, unsigned long magic, + struct tree_descr *files) { struct inode *inode; struct dentry *root; @@ -436,8 +512,6 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files */ inode->i_ino = 1; inode->i_mode = S_IFDIR | 0755; - inode->i_uid = inode->i_gid = 0; - inode->i_blocks = 0; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; @@ -464,8 +538,6 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files if (!inode) goto out; inode->i_mode = S_IFREG | files->mode; - inode->i_uid = inode->i_gid = 0; - inode->i_blocks = 0; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_fop = files->ops; inode->i_ino = i; @@ -530,14 +602,52 @@ 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; + size_t ret; + if (pos < 0) return -EINVAL; - if (pos >= available) + if (pos >= available || !count) + return 0; + if (count > available - pos) + count = available - pos; + ret = copy_to_user(to, from + pos, count); + if (ret == count) + return -EFAULT; + count -= ret; + *ppos = pos + count; + return count; +} + +/** + * 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; - if (copy_to_user(to, from + pos, count)) + res = copy_from_user(to + pos, from, count); + if (res == count) return -EFAULT; + count -= res; *ppos = pos + count; return count; } @@ -579,6 +689,21 @@ ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, * possibly a read which collects the result - which is stored in a * file-local buffer. */ + +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; +} + char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) { struct simple_transaction_argresp *ar; @@ -723,10 +848,11 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf, if (copy_from_user(attr->set_buf, buf, size)) goto out; - ret = len; /* claim we got the whole input */ attr->set_buf[size] = '\0'; val = simple_strtol(attr->set_buf, NULL, 0); - attr->set(attr->data, val); + ret = attr->set(attr->data, val); + if (ret == 0) + ret = len; /* on success, claim we got the whole input */ out: mutex_unlock(&attr->mutex); return ret; @@ -797,6 +923,46 @@ struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, } EXPORT_SYMBOL_GPL(generic_fh_to_parent); +/** + * 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. + */ +int generic_file_fsync(struct file *file, int datasync) +{ + struct writeback_control wbc = { + .sync_mode = WB_SYNC_ALL, + .nr_to_write = 0, /* metadata-only; caller takes care of data */ + }; + struct inode *inode = file->f_mapping->host; + int err; + int ret; + + ret = sync_mapping_buffers(inode->i_mapping); + if (!(inode->i_state & I_DIRTY)) + return ret; + if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) + return ret; + + err = sync_inode(inode, &wbc); + if (ret == 0) + ret = err; + return ret; +} +EXPORT_SYMBOL(generic_file_fsync); + +/* + * No-op implementation of ->fsync for in-memory filesystems. + */ +int noop_fsync(struct file *file, int datasync) +{ + return 0; +} + EXPORT_SYMBOL(dcache_dir_close); EXPORT_SYMBOL(dcache_dir_lseek); EXPORT_SYMBOL(dcache_dir_open); @@ -808,22 +974,22 @@ EXPORT_SYMBOL(simple_write_end); EXPORT_SYMBOL(simple_dir_inode_operations); EXPORT_SYMBOL(simple_dir_operations); EXPORT_SYMBOL(simple_empty); -EXPORT_SYMBOL(d_alloc_name); EXPORT_SYMBOL(simple_fill_super); EXPORT_SYMBOL(simple_getattr); EXPORT_SYMBOL(simple_link); EXPORT_SYMBOL(simple_lookup); EXPORT_SYMBOL(simple_pin_fs); -EXPORT_SYMBOL(simple_prepare_write); EXPORT_SYMBOL(simple_readpage); EXPORT_SYMBOL(simple_release_fs); EXPORT_SYMBOL(simple_rename); EXPORT_SYMBOL(simple_rmdir); EXPORT_SYMBOL(simple_statfs); -EXPORT_SYMBOL(simple_sync_file); +EXPORT_SYMBOL(noop_fsync); EXPORT_SYMBOL(simple_unlink); EXPORT_SYMBOL(simple_read_from_buffer); +EXPORT_SYMBOL(simple_write_to_buffer); EXPORT_SYMBOL(memory_read_from_buffer); +EXPORT_SYMBOL(simple_transaction_set); EXPORT_SYMBOL(simple_transaction_get); EXPORT_SYMBOL(simple_transaction_read); EXPORT_SYMBOL(simple_transaction_release);