From e3014d14a81edde488d9a6758eea8afc41752d2d Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 29 Aug 2016 15:38:11 -0400 Subject: [PATCH] ext4: fixup free space calculations when expanding inodes Conditions checking whether there is enough free space in an xattr block and when xattr is large enough to make enough space in the inode forgot to account for the fact that inode need not be completely filled up with xattrs. Thus we could move unnecessarily many xattrs out of inode or even falsely claim there is not enough space to expand the inode. We also forgot to update the amount of free space in xattr block when moving more xattrs and thus could decide to move too big xattr resulting in unexpected failure. Fix these problems by properly updating free space in the inode and xattr block as we move xattrs. To simplify the math, avoid shifting xattrs after removing each one xattr and instead just shift xattrs only once there is enough free space in the inode. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- fs/ext4/xattr.c | 58 ++++++++++++++++++++----------------------------- 1 file changed, 24 insertions(+), 34 deletions(-) diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 2eb935ca5d9e..22d2ebcd1f09 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1350,7 +1350,8 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, struct ext4_xattr_ibody_find *is = NULL; struct ext4_xattr_block_find *bs = NULL; char *buffer = NULL, *b_entry_name = NULL; - size_t min_offs, free; + size_t min_offs; + size_t ifree, bfree; int total_ino; void *base, *start, *end; int error = 0, tried_min_extra_isize = 0; @@ -1385,17 +1386,9 @@ retry: if (error) goto cleanup; - free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); - if (free >= isize_diff) { - entry = IFIRST(header); - ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - - new_extra_isize, (void *)raw_inode + - EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, - (void *)header, total_ino, - inode->i_sb->s_blocksize); - EXT4_I(inode)->i_extra_isize = new_extra_isize; - goto out; - } + ifree = ext4_xattr_free_space(last, &min_offs, base, &total_ino); + if (ifree >= isize_diff) + goto shift; /* * Enough free space isn't available in the inode, check if @@ -1416,8 +1409,8 @@ retry: first = BFIRST(bh); end = bh->b_data + bh->b_size; min_offs = end - base; - free = ext4_xattr_free_space(first, &min_offs, base, NULL); - if (free < isize_diff) { + bfree = ext4_xattr_free_space(first, &min_offs, base, NULL); + if (bfree + ifree < isize_diff) { if (!tried_min_extra_isize && s_min_extra_isize) { tried_min_extra_isize++; new_extra_isize = s_min_extra_isize; @@ -1428,10 +1421,10 @@ retry: goto cleanup; } } else { - free = inode->i_sb->s_blocksize; + bfree = inode->i_sb->s_blocksize; } - while (isize_diff > 0) { + while (isize_diff > ifree) { size_t offs, size, entry_size; struct ext4_xattr_entry *small_entry = NULL; struct ext4_xattr_info i = { @@ -1439,7 +1432,6 @@ retry: .value_len = 0, }; unsigned int total_size; /* EA entry size + value size */ - unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ unsigned int min_total_size = ~0U; is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); @@ -1461,8 +1453,9 @@ retry: total_size = EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + EXT4_XATTR_LEN(last->e_name_len); - if (total_size <= free && total_size < min_total_size) { - if (total_size < isize_diff) { + if (total_size <= bfree && + total_size < min_total_size) { + if (total_size + ifree < isize_diff) { small_entry = last; } else { entry = last; @@ -1491,6 +1484,7 @@ retry: offs = le16_to_cpu(entry->e_value_offs); size = le32_to_cpu(entry->e_value_size); entry_size = EXT4_XATTR_LEN(entry->e_name_len); + total_size = entry_size + EXT4_XATTR_SIZE(size); i.name_index = entry->e_name_index, buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); @@ -1518,21 +1512,8 @@ retry: if (error) goto cleanup; total_ino -= entry_size; - - entry = IFIRST(header); - if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff) - shift_bytes = isize_diff; - else - shift_bytes = entry_size + EXT4_XATTR_SIZE(size); - /* Adjust the offsets and shift the remaining entries ahead */ - ext4_xattr_shift_entries(entry, -shift_bytes, - (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + - EXT4_I(inode)->i_extra_isize + shift_bytes, - (void *)header, total_ino, inode->i_sb->s_blocksize); - - isize_diff -= shift_bytes; - EXT4_I(inode)->i_extra_isize += shift_bytes; - header = IHDR(inode, raw_inode); + ifree += total_size; + bfree -= total_size; i.name = b_entry_name; i.value = buffer; @@ -1553,6 +1534,15 @@ retry: kfree(is); kfree(bs); } + +shift: + /* Adjust the offsets and shift the remaining entries ahead */ + entry = IFIRST(header); + ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize + - new_extra_isize, (void *)raw_inode + + EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, + (void *)header, total_ino, inode->i_sb->s_blocksize); + EXT4_I(inode)->i_extra_isize = new_extra_isize; brelse(bh); out: ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); -- 2.20.1