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authorAlex Tomas <alex@clusterfs.com>2007-07-18 09:19:09 -0400
committerTheodore Ts'o <tytso@mit.edu>2007-07-18 09:19:09 -0400
commitc29c0ae7f282828da3695167ed870131798348d9 (patch)
treec2d2edc01981892014cfb17fca499a6f2913384d /fs/ext4/extents.c
parentff9ddf7e847c4dc533f119efb6c77a6e57ab6397 (diff)
ext4: Make extents code sanely handle on-disk corruption
Add more run-time checking of extent header fields and remove BUG_ON checks so we don't panic the kernel just because the on-disk filesystem is corrupted. Signed-off-by: Alex Tomas <alex@clusterfs.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/extents.c')
-rw-r--r--fs/ext4/extents.c144
1 files changed, 86 insertions, 58 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 77146b826a13..96264b2ef0a3 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -92,36 +92,6 @@ static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
92 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); 92 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
93} 93}
94 94
95static int ext4_ext_check_header(const char *function, struct inode *inode,
96 struct ext4_extent_header *eh)
97{
98 const char *error_msg = NULL;
99
100 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
101 error_msg = "invalid magic";
102 goto corrupted;
103 }
104 if (unlikely(eh->eh_max == 0)) {
105 error_msg = "invalid eh_max";
106 goto corrupted;
107 }
108 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
109 error_msg = "invalid eh_entries";
110 goto corrupted;
111 }
112 return 0;
113
114corrupted:
115 ext4_error(inode->i_sb, function,
116 "bad header in inode #%lu: %s - magic %x, "
117 "entries %u, max %u, depth %u",
118 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
119 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
120 le16_to_cpu(eh->eh_depth));
121
122 return -EIO;
123}
124
125static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed) 95static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
126{ 96{
127 int err; 97 int err;
@@ -270,6 +240,70 @@ static int ext4_ext_space_root_idx(struct inode *inode)
270 return size; 240 return size;
271} 241}
272 242
243static int
244ext4_ext_max_entries(struct inode *inode, int depth)
245{
246 int max;
247
248 if (depth == ext_depth(inode)) {
249 if (depth == 0)
250 max = ext4_ext_space_root(inode);
251 else
252 max = ext4_ext_space_root_idx(inode);
253 } else {
254 if (depth == 0)
255 max = ext4_ext_space_block(inode);
256 else
257 max = ext4_ext_space_block_idx(inode);
258 }
259
260 return max;
261}
262
263static int __ext4_ext_check_header(const char *function, struct inode *inode,
264 struct ext4_extent_header *eh,
265 int depth)
266{
267 const char *error_msg;
268 int max = 0;
269
270 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
271 error_msg = "invalid magic";
272 goto corrupted;
273 }
274 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
275 error_msg = "unexpected eh_depth";
276 goto corrupted;
277 }
278 if (unlikely(eh->eh_max == 0)) {
279 error_msg = "invalid eh_max";
280 goto corrupted;
281 }
282 max = ext4_ext_max_entries(inode, depth);
283 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
284 error_msg = "too large eh_max";
285 goto corrupted;
286 }
287 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
288 error_msg = "invalid eh_entries";
289 goto corrupted;
290 }
291 return 0;
292
293corrupted:
294 ext4_error(inode->i_sb, function,
295 "bad header in inode #%lu: %s - magic %x, "
296 "entries %u, max %u(%u), depth %u(%u)",
297 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
298 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
299 max, le16_to_cpu(eh->eh_depth), depth);
300
301 return -EIO;
302}
303
304#define ext4_ext_check_header(inode, eh, depth) \
305 __ext4_ext_check_header(__FUNCTION__, inode, eh, depth)
306
273#ifdef EXT_DEBUG 307#ifdef EXT_DEBUG
274static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) 308static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
275{ 309{
@@ -330,6 +364,7 @@ static void ext4_ext_drop_refs(struct ext4_ext_path *path)
330/* 364/*
331 * ext4_ext_binsearch_idx: 365 * ext4_ext_binsearch_idx:
332 * binary search for the closest index of the given block 366 * binary search for the closest index of the given block
367 * the header must be checked before calling this
333 */ 368 */
334static void 369static void
335ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block) 370ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
@@ -337,9 +372,6 @@ ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int bloc
337 struct ext4_extent_header *eh = path->p_hdr; 372 struct ext4_extent_header *eh = path->p_hdr;
338 struct ext4_extent_idx *r, *l, *m; 373 struct ext4_extent_idx *r, *l, *m;
339 374
340 BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
341 BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
342 BUG_ON(le16_to_cpu(eh->eh_entries) <= 0);
343 375
344 ext_debug("binsearch for %d(idx): ", block); 376 ext_debug("binsearch for %d(idx): ", block);
345 377
@@ -389,6 +421,7 @@ ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int bloc
389/* 421/*
390 * ext4_ext_binsearch: 422 * ext4_ext_binsearch:
391 * binary search for closest extent of the given block 423 * binary search for closest extent of the given block
424 * the header must be checked before calling this
392 */ 425 */
393static void 426static void
394ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block) 427ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
@@ -396,9 +429,6 @@ ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
396 struct ext4_extent_header *eh = path->p_hdr; 429 struct ext4_extent_header *eh = path->p_hdr;
397 struct ext4_extent *r, *l, *m; 430 struct ext4_extent *r, *l, *m;
398 431
399 BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
400 BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
401
402 if (eh->eh_entries == 0) { 432 if (eh->eh_entries == 0) {
403 /* 433 /*
404 * this leaf is empty: 434 * this leaf is empty:
@@ -469,11 +499,10 @@ ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
469 short int depth, i, ppos = 0, alloc = 0; 499 short int depth, i, ppos = 0, alloc = 0;
470 500
471 eh = ext_inode_hdr(inode); 501 eh = ext_inode_hdr(inode);
472 BUG_ON(eh == NULL); 502 depth = ext_depth(inode);
473 if (ext4_ext_check_header(__FUNCTION__, inode, eh)) 503 if (ext4_ext_check_header(inode, eh, depth))
474 return ERR_PTR(-EIO); 504 return ERR_PTR(-EIO);
475 505
476 i = depth = ext_depth(inode);
477 506
478 /* account possible depth increase */ 507 /* account possible depth increase */
479 if (!path) { 508 if (!path) {
@@ -485,10 +514,12 @@ ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
485 } 514 }
486 path[0].p_hdr = eh; 515 path[0].p_hdr = eh;
487 516
517 i = depth;
488 /* walk through the tree */ 518 /* walk through the tree */
489 while (i) { 519 while (i) {
490 ext_debug("depth %d: num %d, max %d\n", 520 ext_debug("depth %d: num %d, max %d\n",
491 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); 521 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
522
492 ext4_ext_binsearch_idx(inode, path + ppos, block); 523 ext4_ext_binsearch_idx(inode, path + ppos, block);
493 path[ppos].p_block = idx_pblock(path[ppos].p_idx); 524 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
494 path[ppos].p_depth = i; 525 path[ppos].p_depth = i;
@@ -505,7 +536,7 @@ ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
505 path[ppos].p_hdr = eh; 536 path[ppos].p_hdr = eh;
506 i--; 537 i--;
507 538
508 if (ext4_ext_check_header(__FUNCTION__, inode, eh)) 539 if (ext4_ext_check_header(inode, eh, i))
509 goto err; 540 goto err;
510 } 541 }
511 542
@@ -514,9 +545,6 @@ ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
514 path[ppos].p_ext = NULL; 545 path[ppos].p_ext = NULL;
515 path[ppos].p_idx = NULL; 546 path[ppos].p_idx = NULL;
516 547
517 if (ext4_ext_check_header(__FUNCTION__, inode, eh))
518 goto err;
519
520 /* find extent */ 548 /* find extent */
521 ext4_ext_binsearch(inode, path + ppos, block); 549 ext4_ext_binsearch(inode, path + ppos, block);
522 550
@@ -1738,13 +1766,12 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
1738 unsigned uninitialized = 0; 1766 unsigned uninitialized = 0;
1739 struct ext4_extent *ex; 1767 struct ext4_extent *ex;
1740 1768
1769 /* the header must be checked already in ext4_ext_remove_space() */
1741 ext_debug("truncate since %lu in leaf\n", start); 1770 ext_debug("truncate since %lu in leaf\n", start);
1742 if (!path[depth].p_hdr) 1771 if (!path[depth].p_hdr)
1743 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); 1772 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
1744 eh = path[depth].p_hdr; 1773 eh = path[depth].p_hdr;
1745 BUG_ON(eh == NULL); 1774 BUG_ON(eh == NULL);
1746 BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
1747 BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
1748 1775
1749 /* find where to start removing */ 1776 /* find where to start removing */
1750 ex = EXT_LAST_EXTENT(eh); 1777 ex = EXT_LAST_EXTENT(eh);
@@ -1898,7 +1925,7 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
1898 return -ENOMEM; 1925 return -ENOMEM;
1899 } 1926 }
1900 path[0].p_hdr = ext_inode_hdr(inode); 1927 path[0].p_hdr = ext_inode_hdr(inode);
1901 if (ext4_ext_check_header(__FUNCTION__, inode, path[0].p_hdr)) { 1928 if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) {
1902 err = -EIO; 1929 err = -EIO;
1903 goto out; 1930 goto out;
1904 } 1931 }
@@ -1919,17 +1946,8 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
1919 if (!path[i].p_hdr) { 1946 if (!path[i].p_hdr) {
1920 ext_debug("initialize header\n"); 1947 ext_debug("initialize header\n");
1921 path[i].p_hdr = ext_block_hdr(path[i].p_bh); 1948 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
1922 if (ext4_ext_check_header(__FUNCTION__, inode,
1923 path[i].p_hdr)) {
1924 err = -EIO;
1925 goto out;
1926 }
1927 } 1949 }
1928 1950
1929 BUG_ON(le16_to_cpu(path[i].p_hdr->eh_entries)
1930 > le16_to_cpu(path[i].p_hdr->eh_max));
1931 BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC);
1932
1933 if (!path[i].p_idx) { 1951 if (!path[i].p_idx) {
1934 /* this level hasn't been touched yet */ 1952 /* this level hasn't been touched yet */
1935 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); 1953 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
@@ -1946,17 +1964,27 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
1946 i, EXT_FIRST_INDEX(path[i].p_hdr), 1964 i, EXT_FIRST_INDEX(path[i].p_hdr),
1947 path[i].p_idx); 1965 path[i].p_idx);
1948 if (ext4_ext_more_to_rm(path + i)) { 1966 if (ext4_ext_more_to_rm(path + i)) {
1967 struct buffer_head *bh;
1949 /* go to the next level */ 1968 /* go to the next level */
1950 ext_debug("move to level %d (block %llu)\n", 1969 ext_debug("move to level %d (block %llu)\n",
1951 i + 1, idx_pblock(path[i].p_idx)); 1970 i + 1, idx_pblock(path[i].p_idx));
1952 memset(path + i + 1, 0, sizeof(*path)); 1971 memset(path + i + 1, 0, sizeof(*path));
1953 path[i+1].p_bh = 1972 bh = sb_bread(sb, idx_pblock(path[i].p_idx));
1954 sb_bread(sb, idx_pblock(path[i].p_idx)); 1973 if (!bh) {
1955 if (!path[i+1].p_bh) {
1956 /* should we reset i_size? */ 1974 /* should we reset i_size? */
1957 err = -EIO; 1975 err = -EIO;
1958 break; 1976 break;
1959 } 1977 }
1978 if (WARN_ON(i + 1 > depth)) {
1979 err = -EIO;
1980 break;
1981 }
1982 if (ext4_ext_check_header(inode, ext_block_hdr(bh),
1983 depth - i - 1)) {
1984 err = -EIO;
1985 break;
1986 }
1987 path[i + 1].p_bh = bh;
1960 1988
1961 /* save actual number of indexes since this 1989 /* save actual number of indexes since this
1962 * number is changed at the next iteration */ 1990 * number is changed at the next iteration */