diff options
| -rw-r--r-- | fs/buffer.c | 60 | ||||
| -rw-r--r-- | fs/fat/file.c | 31 | ||||
| -rw-r--r-- | include/linux/buffer_head.h | 3 |
3 files changed, 76 insertions, 18 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index 5287be1..5502323 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2160,11 +2160,12 @@ int block_read_full_page(struct page *page, get_block_t *get_block) * truncates. Uses prepare/commit_write to allow the filesystem to * deal with the hole. */ -int generic_cont_expand(struct inode *inode, loff_t size) +static int __generic_cont_expand(struct inode *inode, loff_t size, + pgoff_t index, unsigned int offset) { struct address_space *mapping = inode->i_mapping; struct page *page; - unsigned long index, offset, limit; + unsigned long limit; int err; err = -EFBIG; @@ -2176,24 +2177,24 @@ int generic_cont_expand(struct inode *inode, loff_t size) if (size > inode->i_sb->s_maxbytes) goto out; - offset = (size & (PAGE_CACHE_SIZE-1)); /* Within page */ - - /* ugh. in prepare/commit_write, if from==to==start of block, we - ** skip the prepare. make sure we never send an offset for the start - ** of a block - */ - if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) { - offset++; - } - index = size >> PAGE_CACHE_SHIFT; err = -ENOMEM; page = grab_cache_page(mapping, index); if (!page) goto out; err = mapping->a_ops->prepare_write(NULL, page, offset, offset); - if (!err) { - err = mapping->a_ops->commit_write(NULL, page, offset, offset); + if (err) { + /* + * ->prepare_write() may have instantiated a few blocks + * outside i_size. Trim these off again. + */ + unlock_page(page); + page_cache_release(page); + vmtruncate(inode, inode->i_size); + goto out; } + + err = mapping->a_ops->commit_write(NULL, page, offset, offset); + unlock_page(page); page_cache_release(page); if (err > 0) @@ -2202,6 +2203,36 @@ out: return err; } +int generic_cont_expand(struct inode *inode, loff_t size) +{ + pgoff_t index; + unsigned int offset; + + offset = (size & (PAGE_CACHE_SIZE - 1)); /* Within page */ + + /* ugh. in prepare/commit_write, if from==to==start of block, we + ** skip the prepare. make sure we never send an offset for the start + ** of a block + */ + if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) { + /* caller must handle this extra byte. */ + offset++; + } + index = size >> PAGE_CACHE_SHIFT; + + return __generic_cont_expand(inode, size, index, offset); +} + +int generic_cont_expand_simple(struct inode *inode, loff_t size) +{ + loff_t pos = size - 1; + pgoff_t index = pos >> PAGE_CACHE_SHIFT; + unsigned int offset = (pos & (PAGE_CACHE_SIZE - 1)) + 1; + + /* prepare/commit_write can handle even if from==to==start of block. */ + return __generic_cont_expand(inode, size, index, offset); +} + /* * For moronic filesystems that do not allow holes in file. * We may have to extend the file. @@ -3145,6 +3176,7 @@ EXPORT_SYMBOL(fsync_bdev); EXPORT_SYMBOL(generic_block_bmap); EXPORT_SYMBOL(generic_commit_write); EXPORT_SYMBOL(generic_cont_expand); +EXPORT_SYMBOL(generic_cont_expand_simple); EXPORT_SYMBOL(init_buffer); EXPORT_SYMBOL(invalidate_bdev); EXPORT_SYMBOL(ll_rw_block); diff --git a/fs/fat/file.c b/fs/fat/file.c index 15229fe..9b07c32 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -11,6 +11,7 @@ #include <linux/msdos_fs.h> #include <linux/smp_lock.h> #include <linux/buffer_head.h> +#include <linux/writeback.h> int fat_generic_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) @@ -124,6 +125,24 @@ struct file_operations fat_file_operations = { .sendfile = generic_file_sendfile, }; +static int fat_cont_expand(struct inode *inode, loff_t size) +{ + struct address_space *mapping = inode->i_mapping; + loff_t start = inode->i_size, count = size - inode->i_size; + int err; + + err = generic_cont_expand_simple(inode, size); + if (err) + goto out; + + inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; + mark_inode_dirty(inode); + if (IS_SYNC(inode)) + err = sync_page_range_nolock(inode, mapping, start, count); +out: + return err; +} + int fat_notify_change(struct dentry *dentry, struct iattr *attr) { struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb); @@ -132,11 +151,17 @@ int fat_notify_change(struct dentry *dentry, struct iattr *attr) lock_kernel(); - /* FAT cannot truncate to a longer file */ + /* + * Expand the file. Since inode_setattr() updates ->i_size + * before calling the ->truncate(), but FAT needs to fill the + * hole before it. + */ if (attr->ia_valid & ATTR_SIZE) { if (attr->ia_size > inode->i_size) { - error = -EPERM; - goto out; + error = fat_cont_expand(inode, attr->ia_size); + if (error || attr->ia_valid == ATTR_SIZE) + goto out; + attr->ia_valid &= ~ATTR_SIZE; } } diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 1db061b..9f159ba 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -197,7 +197,8 @@ int block_read_full_page(struct page*, get_block_t*); int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*); int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*, loff_t *); -int generic_cont_expand(struct inode *inode, loff_t size) ; +int generic_cont_expand(struct inode *inode, loff_t size); +int generic_cont_expand_simple(struct inode *inode, loff_t size); int block_commit_write(struct page *page, unsigned from, unsigned to); int block_sync_page(struct page *); sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); |