diff options
| -rw-r--r-- | fs/btrfs/super.c | 222 |
1 files changed, 213 insertions, 9 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 151c100..7914b31 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -9,6 +9,8 @@ #include <linux/smp_lock.h> #include <linux/backing-dev.h> #include <linux/mpage.h> +#include <linux/swap.h> +#include <linux/writeback.h> #include "ctree.h" #include "disk-io.h" #include "transaction.h" @@ -755,7 +757,7 @@ printk("btrfs sync_fs\n"); return 0; } -static int btrfs_get_block(struct inode *inode, sector_t iblock, +static int btrfs_get_block_lock(struct inode *inode, sector_t iblock, struct buffer_head *result, int create) { int ret; @@ -772,7 +774,6 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock, struct btrfs_disk_key *found_key; btrfs_init_path(&path); - mutex_lock(&root->fs_info->fs_mutex); if (create) trans = btrfs_start_transaction(root, 1); @@ -848,6 +849,16 @@ allocate: out: if (trans) btrfs_end_transaction(trans, root); + return err; +} + +static int btrfs_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *result, int create) +{ + int err; + struct btrfs_root *root = btrfs_sb(inode->i_sb); + mutex_lock(&root->fs_info->fs_mutex); + err = btrfs_get_block_lock(inode, iblock, result, create); mutex_unlock(&root->fs_info->fs_mutex); return err; } @@ -855,8 +866,15 @@ out: static int btrfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) { + WARN_ON(1); return nobh_prepare_write(page, from, to, btrfs_get_block); } +static int btrfs_commit_write(struct file *file, struct page *page, + unsigned from, unsigned to) +{ + WARN_ON(1); + return nobh_commit_write(file, page, from, to); +} static void btrfs_write_super(struct super_block *sb) { @@ -903,6 +921,196 @@ static void btrfs_truncate(struct inode *inode) mark_inode_dirty(inode); } +static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes, + struct page **prepared_pages, + const char __user * buf) +{ + long page_fault = 0; + int i; + int offset = pos & (PAGE_CACHE_SIZE - 1); + + for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) { + size_t count = min_t(size_t, + PAGE_CACHE_SIZE - offset, write_bytes); + struct page *page = prepared_pages[i]; + fault_in_pages_readable(buf, count); + + /* Copy data from userspace to the current page */ + kmap(page); + page_fault = __copy_from_user(page_address(page) + offset, + buf, count); + /* Flush processor's dcache for this page */ + flush_dcache_page(page); + kunmap(page); + buf += count; + write_bytes -= count; + + if (page_fault) + break; + } + return page_fault ? -EFAULT : 0; +} + +static void btrfs_drop_pages(struct page **pages, size_t num_pages) +{ + size_t i; + for (i = 0; i < num_pages; i++) { + if (!pages[i]) + break; + unlock_page(pages[i]); + mark_page_accessed(pages[i]); + page_cache_release(pages[i]); + } +} +static int dirty_and_release_pages(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct file *file, + struct page **pages, + size_t num_pages, + loff_t pos, + size_t write_bytes) +{ + int i; + int offset; + int err = 0; + int ret; + int this_write; + + for (i = 0; i < num_pages; i++) { + offset = pos & (PAGE_CACHE_SIZE -1); + this_write = min(PAGE_CACHE_SIZE - offset, write_bytes); + ret = nobh_commit_write(file, pages[i], offset, + offset + this_write); + pos += this_write; + if (ret) { + err = ret; + goto failed; + } + WARN_ON(this_write > write_bytes); + write_bytes -= this_write; + } +failed: + return err; +} + +static int prepare_pages(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct file *file, + struct page **pages, + size_t num_pages, + loff_t pos, + size_t write_bytes) +{ + int i; + unsigned long index = pos >> PAGE_CACHE_SHIFT; + struct inode *inode = file->f_path.dentry->d_inode; + int offset; + int err = 0; + int ret; + int this_write; + loff_t isize = i_size_read(inode); + + memset(pages, 0, num_pages * sizeof(struct page *)); + + for (i = 0; i < num_pages; i++) { + pages[i] = grab_cache_page(inode->i_mapping, index + i); + if (!pages[i]) { + err = -ENOMEM; + goto failed_release; + } + offset = pos & (PAGE_CACHE_SIZE -1); + this_write = min(PAGE_CACHE_SIZE - offset, write_bytes); + ret = nobh_prepare_write(pages[i], offset, + offset + this_write, + btrfs_get_block_lock); + pos += this_write; + if (ret) { + err = ret; + goto failed_truncate; + } + WARN_ON(this_write > write_bytes); + write_bytes -= this_write; + } + return 0; + +failed_release: + btrfs_drop_pages(pages, num_pages); + return err; + +failed_truncate: + btrfs_drop_pages(pages, num_pages); + if (pos > isize) + vmtruncate(inode, isize); + return err; +} + +static ssize_t btrfs_file_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + loff_t pos; + size_t num_written = 0; + int err = 0; + int ret = 0; + struct btrfs_trans_handle *trans; + struct inode *inode = file->f_path.dentry->d_inode; + struct btrfs_root *root = btrfs_sb(inode->i_sb); + struct page *pages[1]; + + if (file->f_flags & O_DIRECT) + return -EINVAL; + pos = *ppos; + + vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); + current->backing_dev_info = inode->i_mapping->backing_dev_info; + err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); + if (err) + goto out; + if (count == 0) + goto out; + err = remove_suid(file->f_path.dentry); + if (err) + goto out; + file_update_time(file); + mutex_lock(&inode->i_mutex); + while(count > 0) { + size_t offset = pos & (PAGE_CACHE_SIZE - 1); + size_t write_bytes = min(count, PAGE_CACHE_SIZE - offset); + size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >> + PAGE_CACHE_SHIFT; + mutex_lock(&root->fs_info->fs_mutex); + trans = btrfs_start_transaction(root, 1); + + ret = prepare_pages(trans, root, file, pages, num_pages, + pos, write_bytes); + BUG_ON(ret); + ret = btrfs_copy_from_user(pos, num_pages, + write_bytes, pages, buf); + BUG_ON(ret); + + mutex_unlock(&root->fs_info->fs_mutex); + + ret = dirty_and_release_pages(trans, root, file, pages, + num_pages, pos, write_bytes); + BUG_ON(ret); + btrfs_drop_pages(pages, num_pages); + + ret = btrfs_end_transaction(trans, root); + + buf += write_bytes; + count -= write_bytes; + pos += write_bytes; + num_written += write_bytes; + + balance_dirty_pages_ratelimited(inode->i_mapping); + cond_resched(); + } + mutex_unlock(&inode->i_mutex); +out: + *ppos = pos; + current->backing_dev_info = NULL; + return num_written ? num_written : err; +} + static int btrfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { @@ -948,7 +1156,7 @@ static struct address_space_operations btrfs_aops = { .writepage = btrfs_writepage, .sync_page = block_sync_page, .prepare_write = btrfs_prepare_write, - .commit_write = nobh_commit_write, + .commit_write = btrfs_commit_write, }; static struct inode_operations btrfs_file_inode_operations = { @@ -958,14 +1166,10 @@ static struct inode_operations btrfs_file_inode_operations = { static struct file_operations btrfs_file_operations = { .llseek = generic_file_llseek, .read = do_sync_read, - .write = do_sync_write, - .aio_read = generic_file_aio_read, - .aio_write = generic_file_aio_write, + .aio_read = generic_file_aio_read, + .write = btrfs_file_write, .mmap = generic_file_mmap, .open = generic_file_open, - .sendfile = generic_file_sendfile, - .splice_read = generic_file_splice_read, - .splice_write = generic_file_splice_write, }; static int __init init_btrfs_fs(void) |