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Btrfs: make sure we don't overflow the free space cache crc page 

The free space cache uses only one page for crcs right now,
which means we can't have a cache file bigger than the
crcs we can fit in the first page.  This adds a check to
enforce that restriction.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2011-06-03 01:26:53 -04:00
parent 17aca1c987
commit 211f96c24f
1 changed files with 19 additions and 8 deletions
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27
fs/btrfs/free-space-cache.c
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@ -590,10 +590,25 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
/* Since the first page has all of our checksums and our generation we
* need to calculate the offset into the page that we can start writing
* our entries.
*/
first_page_offset = (sizeof(u32) * num_pages) + sizeof(u64);
filemap_write_and_wait(inode->i_mapping);
btrfs_wait_ordered_range(inode, inode->i_size &
~(root->sectorsize - 1), (u64)-1);
/* make sure we don't overflow that first page */
if (first_page_offset + sizeof(struct btrfs_free_space_entry) >= PAGE_CACHE_SIZE) {
/* this is really the same as running out of space, where we also return 0 */
printk(KERN_CRIT "Btrfs: free space cache was too big for the crc page\n");
ret = 0;
goto out_update;
}
/* We need a checksum per page. */
crc = checksums = kzalloc(sizeof(u32) * num_pages, GFP_NOFS);
if (!crc)
@ -605,12 +620,6 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
return -1;
}
/* Since the first page has all of our checksums and our generation we
* need to calculate the offset into the page that we can start writing
* our entries.
*/
first_page_offset = (sizeof(u32) * num_pages) + sizeof(u64);
/* Get the cluster for this block_group if it exists */
if (block_group && !list_empty(&block_group->cluster_list))
cluster = list_entry(block_group->cluster_list.next,
@ -872,12 +881,14 @@ int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
ret = 1;
out_free:
kfree(checksums);
kfree(pages);
out_update:
if (ret != 1) {
invalidate_inode_pages2_range(inode->i_mapping, 0, index);
BTRFS_I(inode)->generation = 0;
}
kfree(checksums);
kfree(pages);
btrfs_update_inode(trans, root, inode);
return ret;
}