From 784b4e29a26617589edd290dd2919735e190c06e Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Sun, 21 Nov 2010 22:20:49 -0500 Subject: Btrfs: add migrate page for metadata inode Migrate page will directly call the btrfs btree writepage function, which isn't actually allowed. Our writepage assumes that you have locked the extent_buffer and flagged the block as written. Without doing these steps, we can corrupt metadata blocks. A later commit will remove the btree writepage function since it is really only safely used internally by btrfs. We use writepages for everything else. Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/disk-io.c') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index b40dfe48017b..a67b98d58c2a 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "compat.h" #include "ctree.h" #include "disk-io.h" @@ -355,6 +356,8 @@ static int csum_dirty_buffer(struct btrfs_root *root, struct page *page) ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE, btrfs_header_generation(eb)); BUG_ON(ret); + WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN)); + found_start = btrfs_header_bytenr(eb); if (found_start != start) { WARN_ON(1); @@ -693,6 +696,26 @@ static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio, __btree_submit_bio_done); } +static int btree_migratepage(struct address_space *mapping, + struct page *newpage, struct page *page) +{ + /* + * we can't safely write a btree page from here, + * we haven't done the locking hook + */ + if (PageDirty(page)) + return -EAGAIN; + /* + * Buffers may be managed in a filesystem specific way. + * We must have no buffers or drop them. + */ + if (page_has_private(page) && + !try_to_release_page(page, GFP_KERNEL)) + return -EAGAIN; + + return migrate_page(mapping, newpage, page); +} + static int btree_writepage(struct page *page, struct writeback_control *wbc) { struct extent_io_tree *tree; @@ -707,8 +730,7 @@ static int btree_writepage(struct page *page, struct writeback_control *wbc) } redirty_page_for_writepage(wbc, page); - eb = btrfs_find_tree_block(root, page_offset(page), - PAGE_CACHE_SIZE); + eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE); WARN_ON(!eb); was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags); @@ -799,6 +821,7 @@ static const struct address_space_operations btree_aops = { .releasepage = btree_releasepage, .invalidatepage = btree_invalidatepage, .sync_page = block_sync_page, + .migratepage = btree_migratepage, }; int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize, -- cgit v1.2.3 From 450ba0ea06b6ed3612d27f2b7127a9de4160f285 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 19 Nov 2010 14:59:15 -0500 Subject: Btrfs: setup blank root and fs_info for mount time There is a problem with how we use sget, it searches through the list of supers attached to the fs_type looking for a super with the same fs_devices as what we're trying to mount. This depends on sb->s_fs_info being filled, but we don't fill that in until we get to btrfs_fill_super, so we could hit supers on the fs_type super list that have a null s_fs_info. In order to fix that we need to go ahead and setup a blank root with a blank fs_info to hold fs_devices, that way our test will work out right and then we can set s_fs_info in btrfs_set_super, and then open_ctree will simply use our pre-allocated root and fs_info when setting everything up. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 6 ++---- fs/btrfs/super.c | 34 +++++++++++++++++++++++++++++++--- 2 files changed, 33 insertions(+), 7 deletions(-) (limited to 'fs/btrfs/disk-io.c') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a67b98d58c2a..57c9d8eeb7dc 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1561,10 +1561,8 @@ struct btrfs_root *open_ctree(struct super_block *sb, GFP_NOFS); struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); - struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root), - GFP_NOFS); - struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info), - GFP_NOFS); + struct btrfs_root *tree_root = btrfs_sb(sb); + struct btrfs_fs_info *fs_info = tree_root->fs_info; struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root), diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 141fb317d3bc..47bf67cbe6bf 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -563,7 +563,7 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs) static int btrfs_test_super(struct super_block *s, void *data) { - struct btrfs_fs_devices *test_fs_devices = data; + struct btrfs_root *test_root = data; struct btrfs_root *root = btrfs_sb(s); /* @@ -572,9 +572,17 @@ static int btrfs_test_super(struct super_block *s, void *data) */ if (!atomic_read(&s->s_active)) return 0; - return root->fs_info->fs_devices == test_fs_devices; + return root->fs_info->fs_devices == test_root->fs_info->fs_devices; } +static int btrfs_set_super(struct super_block *s, void *data) +{ + s->s_fs_info = data; + + return set_anon_super(s, data); +} + + /* * Find a superblock for the given device / mount point. * @@ -588,6 +596,8 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, struct super_block *s; struct dentry *root; struct btrfs_fs_devices *fs_devices = NULL; + struct btrfs_root *tree_root = NULL; + struct btrfs_fs_info *fs_info = NULL; fmode_t mode = FMODE_READ; char *subvol_name = NULL; u64 subvol_objectid = 0; @@ -615,8 +625,24 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, goto error_close_devices; } + /* + * Setup a dummy root and fs_info for test/set super. This is because + * we don't actually fill this stuff out until open_ctree, but we need + * it for searching for existing supers, so this lets us do that and + * then open_ctree will properly initialize everything later. + */ + fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); + tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); + if (!fs_info || !tree_root) { + error = -ENOMEM; + goto error_close_devices; + } + fs_info->tree_root = tree_root; + fs_info->fs_devices = fs_devices; + tree_root->fs_info = fs_info; + bdev = fs_devices->latest_bdev; - s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices); + s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root); if (IS_ERR(s)) goto error_s; @@ -685,6 +711,8 @@ error_s: error = PTR_ERR(s); error_close_devices: btrfs_close_devices(fs_devices); + kfree(fs_info); + kfree(tree_root); error_free_subvol_name: kfree(subvol_name); return error; -- cgit v1.2.3 From 5a92bc88cef279261d3f138e25850c122df67045 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 29 Nov 2010 09:49:11 -0500 Subject: Btrfs: don't use migrate page without CONFIG_MIGRATION Fixes compile error Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/disk-io.c') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 57c9d8eeb7dc..33b6d459494c 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -712,8 +712,11 @@ static int btree_migratepage(struct address_space *mapping, if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) return -EAGAIN; - +#ifdef CONFIG_MIGRATION return migrate_page(mapping, newpage, page); +#else + return -ENOSYS; +#endif } static int btree_writepage(struct page *page, struct writeback_control *wbc) @@ -821,7 +824,9 @@ static const struct address_space_operations btree_aops = { .releasepage = btree_releasepage, .invalidatepage = btree_invalidatepage, .sync_page = block_sync_page, +#ifdef CONFIG_MIGRATION .migratepage = btree_migratepage, +#endif }; int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize, -- cgit v1.2.3