X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Flibfs.c;h=ea9a6cc9b35c6b08ef1517837d1c05a4d2da47e1;hb=38e712ab3d28d79725eaade02fe8aba51abac196;hp=f2b32d3a9093a58eba69fabdbbbf0bf5ea1ae7a3;hpb=afddba49d18f346e5cc2938b6ed7c512db18ca68;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/libfs.c b/fs/libfs.c index f2b32d3..ea9a6cc 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -5,9 +5,13 @@ #include #include +#include #include #include #include +#include +#include +#include #include @@ -43,7 +47,7 @@ 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, }; @@ -214,9 +218,9 @@ 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_blocksize = 1024; - s->s_blocksize_bits = 10; + s->s_maxbytes = MAX_LFS_FILESIZE; + s->s_blocksize = PAGE_SIZE; + s->s_blocksize_bits = PAGE_SHIFT; s->s_magic = magic; s->s_op = ops ? ops : &simple_super_operations; s->s_time_gran = 1; @@ -230,7 +234,6 @@ 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) { @@ -242,11 +245,11 @@ 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; } @@ -336,75 +339,74 @@ 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) { - void *kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr, 0, from); - memset(kaddr + to, 0, PAGE_CACHE_SIZE - to); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); - } - } - 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); -} - -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); @@ -438,8 +440,6 @@ 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; @@ -466,8 +466,6 @@ 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; @@ -514,19 +512,68 @@ void simple_release_fs(struct vfsmount **mount, int *count) mntput(mnt); } +/** + * 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. + **/ 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; - if (copy_to_user(to, from + pos, count)) + ret = copy_to_user(to, from + pos, count); + if (ret == count) return -EFAULT; + count -= ret; + *ppos = pos + count; + return count; +} + +/** + * 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. + **/ +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; } @@ -536,6 +583,21 @@ ssize_t simple_read_from_buffer(void __user *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; @@ -585,8 +647,8 @@ int simple_transaction_release(struct inode *inode, struct file *file) /* Simple attribute files */ struct simple_attr { - u64 (*get)(void *); - void (*set)(void *, u64); + int (*get)(void *, u64 *); + int (*set)(void *, u64); char get_buf[24]; /* enough to store a u64 and "\n\0" */ char set_buf[24]; void *data; @@ -597,7 +659,7 @@ struct simple_attr { /* 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, - u64 (*get)(void *), void (*set)(void *, u64), + int (*get)(void *, u64 *), int (*set)(void *, u64), const char *fmt) { struct simple_attr *attr; @@ -617,7 +679,7 @@ int simple_attr_open(struct inode *inode, struct file *file, return nonseekable_open(inode, file); } -int simple_attr_close(struct inode *inode, struct file *file) +int simple_attr_release(struct inode *inode, struct file *file) { kfree(file->private_data); return 0; @@ -636,15 +698,24 @@ ssize_t simple_attr_read(struct file *file, char __user *buf, if (!attr->get) return -EACCES; - mutex_lock(&attr->mutex); - if (*ppos) /* continued read */ + ret = mutex_lock_interruptible(&attr->mutex); + if (ret) + return ret; + + if (*ppos) { /* continued read */ size = strlen(attr->get_buf); - else /* first read */ + } else { /* first read */ + u64 val; + ret = attr->get(attr->data, &val); + if (ret) + goto out; + size = scnprintf(attr->get_buf, sizeof(attr->get_buf), - attr->fmt, - (unsigned long long)attr->get(attr->data)); + attr->fmt, (unsigned long long)val); + } ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); +out: mutex_unlock(&attr->mutex); return ret; } @@ -659,25 +730,116 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf, ssize_t ret; attr = file->private_data; - if (!attr->set) return -EACCES; - mutex_lock(&attr->mutex); + ret = mutex_lock_interruptible(&attr->mutex); + if (ret) + return ret; + ret = -EFAULT; size = min(sizeof(attr->set_buf) - 1, len); 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; } +/** + * 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; + } + + return d_obtain_alias(inode); +} +EXPORT_SYMBOL_GPL(generic_fh_to_dentry); + +/** + * generic_fh_to_dentry - generic helper for the fh_to_parent 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 _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; + } + + return d_obtain_alias(inode); +} +EXPORT_SYMBOL_GPL(generic_fh_to_parent); + +int simple_fsync(struct file *file, struct dentry *dentry, 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 = dentry->d_inode; + 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(simple_fsync); + EXPORT_SYMBOL(dcache_dir_close); EXPORT_SYMBOL(dcache_dir_lseek); EXPORT_SYMBOL(dcache_dir_open); @@ -686,17 +848,14 @@ EXPORT_SYMBOL(generic_read_dir); EXPORT_SYMBOL(get_sb_pseudo); EXPORT_SYMBOL(simple_write_begin); EXPORT_SYMBOL(simple_write_end); -EXPORT_SYMBOL(simple_commit_write); 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); @@ -705,10 +864,12 @@ EXPORT_SYMBOL(simple_statfs); EXPORT_SYMBOL(simple_sync_file); EXPORT_SYMBOL(simple_unlink); EXPORT_SYMBOL(simple_read_from_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); EXPORT_SYMBOL_GPL(simple_attr_open); -EXPORT_SYMBOL_GPL(simple_attr_close); +EXPORT_SYMBOL_GPL(simple_attr_release); EXPORT_SYMBOL_GPL(simple_attr_read); EXPORT_SYMBOL_GPL(simple_attr_write);