1 From e3014d14a81edde488d9a6758eea8afc41752d2d Mon Sep 17 00:00:00 2001
2 From: Jan Kara <jack@suse.cz>
3 Date: Mon, 29 Aug 2016 15:38:11 -0400
4 Subject: [PATCH] ext4: fixup free space calculations when expanding inodes
6 Conditions checking whether there is enough free space in an xattr block
7 and when xattr is large enough to make enough space in the inode forgot
8 to account for the fact that inode need not be completely filled up with
9 xattrs. Thus we could move unnecessarily many xattrs out of inode or
10 even falsely claim there is not enough space to expand the inode. We
11 also forgot to update the amount of free space in xattr block when moving
12 more xattrs and thus could decide to move too big xattr resulting in
15 Fix these problems by properly updating free space in the inode and
16 xattr block as we move xattrs. To simplify the math, avoid shifting
17 xattrs after removing each one xattr and instead just shift xattrs only
18 once there is enough free space in the inode.
20 Signed-off-by: Jan Kara <jack@suse.cz>
21 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
23 fs/ext4/xattr.c | 58 ++++++++++++++++++++++++---------------------------------
24 1 file changed, 24 insertions(+), 34 deletions(-)
26 Index: linux-4.4.49-92.14_lustre-vanilla/fs/ext4/xattr.c
27 ===================================================================
28 --- linux-4.4.49-92.14_lustre-vanilla.orig/fs/ext4/xattr.c
29 +++ linux-4.4.49-92.14_lustre-vanilla/fs/ext4/xattr.c
30 @@ -1619,18 +1619,19 @@ retry:
32 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
33 int value_offs_shift, void *to,
34 - void *from, size_t n, int blocksize)
35 + void *from, size_t n)
37 struct ext4_xattr_entry *last = entry;
40 + /* We always shift xattr headers further thus offsets get lower */
41 + BUG_ON(value_offs_shift > 0);
43 /* Adjust the value offsets of the entries */
44 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
45 if (!last->e_value_inum && last->e_value_size) {
46 new_offs = le16_to_cpu(last->e_value_offs) +
48 - BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
50 last->e_value_offs = cpu_to_le16(new_offs);
53 @@ -1651,7 +1652,8 @@ int ext4_expand_extra_isize_ea(struct in
54 struct ext4_xattr_ibody_find *is = NULL;
55 struct ext4_xattr_block_find *bs = NULL;
56 char *buffer = NULL, *b_entry_name = NULL;
57 - size_t min_offs, free;
59 + size_t ifree, bfree;
61 void *base, *start, *end;
62 int error = 0, tried_min_extra_isize = 0;
63 @@ -1682,17 +1684,9 @@ retry:
65 total_ino = sizeof(struct ext4_xattr_ibody_header);
67 - free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
68 - if (free >= isize_diff) {
69 - entry = IFIRST(header);
70 - ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
71 - - new_extra_isize, (void *)raw_inode +
72 - EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
73 - (void *)header, total_ino,
74 - inode->i_sb->s_blocksize);
75 - EXT4_I(inode)->i_extra_isize = new_extra_isize;
78 + ifree = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
79 + if (ifree >= isize_diff)
83 * Enough free space isn't available in the inode, check if
84 @@ -1713,8 +1707,8 @@ retry:
86 end = bh->b_data + bh->b_size;
87 min_offs = end - base;
88 - free = ext4_xattr_free_space(first, &min_offs, base, NULL);
89 - if (free < isize_diff) {
90 + bfree = ext4_xattr_free_space(first, &min_offs, base, NULL);
91 + if (bfree + ifree < isize_diff) {
92 if (!tried_min_extra_isize && s_min_extra_isize) {
93 tried_min_extra_isize++;
94 new_extra_isize = s_min_extra_isize;
95 @@ -1725,10 +1719,10 @@ retry:
99 - free = inode->i_sb->s_blocksize;
100 + bfree = inode->i_sb->s_blocksize;
103 - while (isize_diff > 0) {
104 + while (isize_diff > ifree) {
105 size_t offs, size, entry_size;
106 struct ext4_xattr_entry *small_entry = NULL;
107 struct ext4_xattr_info i = {
108 @@ -1736,7 +1730,6 @@ retry:
111 unsigned int total_size; /* EA entry size + value size */
112 - unsigned int shift_bytes; /* No. of bytes to shift EAs by? */
113 unsigned int min_total_size = ~0U;
115 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
116 @@ -1758,8 +1751,9 @@ retry:
118 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
119 EXT4_XATTR_LEN(last->e_name_len);
120 - if (total_size <= free && total_size < min_total_size) {
121 - if (total_size < isize_diff) {
122 + if (total_size <= bfree &&
123 + total_size < min_total_size) {
124 + if (total_size + ifree < isize_diff) {
128 @@ -1788,6 +1782,7 @@ retry:
129 offs = le16_to_cpu(entry->e_value_offs);
130 size = le32_to_cpu(entry->e_value_size);
131 entry_size = EXT4_XATTR_LEN(entry->e_name_len);
132 + total_size = entry_size + EXT4_XATTR_SIZE(size);
133 i.name_index = entry->e_name_index,
134 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS);
135 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
136 @@ -1815,21 +1810,8 @@ retry:
139 total_ino -= entry_size;
141 - entry = IFIRST(header);
142 - if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff)
143 - shift_bytes = isize_diff;
145 - shift_bytes = entry_size + EXT4_XATTR_SIZE(size);
146 - /* Adjust the offsets and shift the remaining entries ahead */
147 - ext4_xattr_shift_entries(entry, -shift_bytes,
148 - (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
149 - EXT4_I(inode)->i_extra_isize + shift_bytes,
150 - (void *)header, total_ino, inode->i_sb->s_blocksize);
152 - isize_diff -= shift_bytes;
153 - EXT4_I(inode)->i_extra_isize += shift_bytes;
154 - header = IHDR(inode, raw_inode);
155 + ifree += total_size;
156 + bfree -= total_size;
158 i.name = b_entry_name;
160 @@ -1850,6 +1832,15 @@ retry:
166 + /* Adjust the offsets and shift the remaining entries ahead */
167 + entry = IFIRST(header);
168 + ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
169 + - new_extra_isize, (void *)raw_inode +
170 + EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
171 + (void *)header, total_ino);
172 + EXT4_I(inode)->i_extra_isize = new_extra_isize;
175 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);