ext4: limit block allocations for indirect-block files to < 2^32
RFC PATCH 1/1 ext4: limit block allocations for indirect-block files to < 2^32
Today, the ext4 allocator will happily allocate blocks past 2^32 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
This patch limits such allocations to < 2^32, and adds WARN_ONs (maybe should be BUG_ONs) if we do get blocks larger than that.
This should address RH Bug 519471, ext4 bitmap allocator must limit blocks to < 2^32
* ext4_find_goal() is modified to choose a goal < UINT_MAX, so that our starting point is in an acceptable range.
* ext4_xattr_block_set() is modified such that the goal block is < UINT_MAX, as above.
* ext4_mb_regular_allocator() is modified so that the group search does not continue into groups which are too high
* ext4_mb_use_preallocated() has a check that we don't use preallocated space which is too far out
* ext4_alloc_blocks() and ext4_xattr_block_set() add some WARN_ONs
No attempt has been made to limit inode locations to < 2^32, so we may wind up with blocks far from their inodes. Doing this much already will lead to some odd ENOSPC issues when the "lower 32" gets full, and further restricting inodes could make that even weirder.
For high inodes, choosing a goal of the original, % UINT_MAX, may be a bit odd, but then we're in an odd situation anyway, and I don't know of a better heuristic.
Perhaps an ext4-specific #define would be better than UINT_MAX?
The allocator being what it is, I may have missed some spots, so I'd welcome review.
Thanks,
-Eric
---
fs/ext4/inode.c +10 -1
@@ -551,15 +551,21 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)* * Normally this function find the preferred place for block allocation, * returns it. +* Because this is only used for bitmap files, we limit the block nr +* to 32 bits. */ static ext4_fsblk_t ext4_find_goal (struct inode *inode,ext4_lblk_t block,Indirect *partial) { +ext4_fsblk_t goal; +/* * XXX need to get goal block from mballoc's data structures */ -return ext4_find_near (inode, partial); + goal =ext4_find_near (inode, partial); + goal = goal %UINT_MAX ; +return goal; }/**
@@ -640,6 +646,8 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,if (*err) goto failed_out; +WARN_ON (current_block + count >UINT_MAX ); + target -= count;/* allocate blocks for indirect blocks */ while (index < indirect_blks && count) {
@@ -674,6 +682,7 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, ar.flags =EXT4_MB_HINT_DATA ; current_block =ext4_mb_new_blocks (handle, &ar, err); +WARN_ON (current_block + ar.len >UINT_MAX );if (*err && (target == blks)) {/*
fs/ext4/mballoc.c +8 -0
@@ -1943,6 +1943,10 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) sb = ac->ac_sb; sbi =EXT4_SB (sb); ngroups =ext4_get_groups_count (sb); +/* bitmap files are limited to low blocks */ +if (!(EXT4_I (ac->ac_inode)->i_flags &EXT4_EXTENTS_FL )) + ngroups %= (UINT_MAX /EXT4_BLOCKS_PER_GROUP (sb)); +BUG_ON (ac->ac_status ==AC_STATUS_FOUND );/* first, try the goal */
@@ -3382,6 +3386,10 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len)continue ; +if (!(EXT4_I (ac->ac_inode)->i_flags &EXT4_EXTENTS_FL ) && + pa->pa_pstart + pa->pa_len >UINT_MAX ) +continue ; +/* found preallocated blocks, use them */ spin_lock (&pa->pa_lock);if (pa->pa_deleted ==0 && pa->pa_free) {
fs/ext4/xattr.c +12 -2
@@ -810,12 +810,22 @@ inserted:get_bh (new_bh); }else {/* We need to allocate a new block */ -ext4_fsblk_t goal =ext4_group_first_block_no (sb, +ext4_fsblk_t goal, block; + + goal =ext4_group_first_block_no (sb,EXT4_I (inode)->i_block_group); -ext4_fsblk_t block =ext4_new_meta_blocks (handle, inode, + +if (!(EXT4_I (inode)->i_flags &EXT4_EXTENTS_FL )) + goal = goal %UINT_MAX ; + + block =ext4_new_meta_blocks (handle, inode, goal,NULL , &error);if (error) goto cleanup; + +if (!(EXT4_I (inode)->i_flags &EXT4_EXTENTS_FL )) +WARN_ON (block >UINT_MAX ); +ea_idebug (inode,"creating block %d" , block); new_bh =sb_getblk (sb, block);
RFC PATCH v2 1/1 ext4: limit block allocations for indirect-block files to < 2^32
Today, the ext4 allocator will happily allocate blocks past 232 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
This patch limits such allocations to < 232, and adds WARN_ONs (maybe should be BUG_ONs) if we do get blocks larger than that.
This should address RH Bug 519471, ext4 bitmap allocator must limit blocks to < 232
* ext4_find_goal() is modified to choose a goal < UINT_MAX, so that our starting point is in an acceptable range.
* ext4_xattr_block_set() is modified such that the goal block is < UINT_MAX, as above.
* ext4_mb_regular_allocator() is modified so that the group search does not continue into groups which are too high
* ext4_mb_use_preallocated() has a check that we don't use preallocated space which is too far out
* ext4_alloc_blocks() and ext4_xattr_block_set() add some WARN_ONs
No attempt has been made to limit inode locations to < 232, so we may wind up with blocks far from their inodes. Doing this much already will lead to some odd ENOSPC issues when the "lower 32" gets full, and further restricting inodes could make that even weirder.
For high inodes, choosing a goal of the original, % UINT_MAX, may be a bit odd, but then we're in an odd situation anyway, and I don't know of a better heuristic.
Perhaps an ext4-specific #define would be better than UINT_MAX?
The allocator being what it is, I may have missed some spots, so I'd welcome review.
Thanks,
-Eric
---
V2: got modulo-happy in ext4_mb_regular_allocator, just limit ngroups to no more than UINT_MAX.
fs/ext4/inode.c +2 -0
@@ -551,15 +551,21 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)* * Normally this function find the preferred place for block allocation, * returns it. +* Because this is only used for non-extent files, we limit the block nr +* to 32 bits. */
static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
Indirect *partial)
{
+ ext4_fsblk_t goal;
+
/* * XXX need to get goal block from mballoc's data structures */
- return ext4_find_near(inode, partial);
+ goal = ext4_find_near(inode, partial);
+ goal = goal % UINT_MAX;
+ return goal;
}
/**
@@ -640,6 +646,8 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
if (*err) goto failed_out;
+ WARN_ON(current_block + count > UINT_MAX);
+
target -= count;
/* allocate blocks for indirect blocks */
while (index < indirect_blks && count) {
@@ -674,6 +682,7 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
ar.flags = EXT4_MB_HINT_DATA;
current_block = ext4_mb_new_blocks(handle, &ar, err);+ WARN_ON(current_block + ar.len > UINT_MAX);
if (*err && (target == blks)) {
/*fs/ext4/mballoc.c +0 -0
@@ -1943,6 +1943,11 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
sb = ac->ac_sb; sbi = EXT4_SB(sb); ngroups = ext4_get_groups_count(sb);
+ /* non-extent files are limited to low blocks/groups */
+ if (!(EXT4_I(ac->ac_inode)->i_flags & EXT4_EXTENTS_FL))
+ ngroups = min_t(unsigned long, ngroups,
+ (UINT_MAX / EXT4_BLOCKS_PER_GROUP(sb)));
+
BUG_ON(ac->ac_status == AC_STATUS_FOUND); /* first, try the goal */ @@ -3382,6 +3387,10 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len) continue;
+ if (!(EXT4_I(ac->ac_inode)->i_flags & EXT4_EXTENTS_FL) &&
+ pa->pa_pstart + pa->pa_len > UINT_MAX)
+ continue;
+
/* found preallocated blocks, use them */
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 && pa->pa_free) {fs/ext4/xattr.c +0 -0
@@ -810,12 +810,22 @@ inserted:
get_bh(new_bh);
} else {
/* We need to allocate a new block */- ext4_fsblk_t goal = ext4_group_first_block_no(sb,
+ ext4_fsblk_t goal, block;
+
+ goal = ext4_group_first_block_no(sb,
EXT4_I(inode)->i_block_group);
- ext4_fsblk_t block = ext4_new_meta_blocks(handle, inode,
+
+ if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+ goal = goal % UINT_MAX;
+
+ block = ext4_new_meta_blocks(handle, inode,
goal, NULL, &error); if (error) goto cleanup;
+
+ if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+ WARN_ON(block > UINT_MAX);
+
ea_idebug(inode, "creating block %d", block); new_bh = sb_getblk(sb, block);
Quoted 7 lines · Eric Sandeen
Today, the ext4 allocator will happily allocate blocks past 232 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
This patch limits such allocations to < 2^32, and adds
WARN_ONs(maybe should beBUG_ONs) if we do get blocks larger than that.
Eric, thanks for making the patch.
Quoted 8 lines
This should address RH Bug 519471, ext4 bitmap allocator must limit blocks to < 2^32
*
ext4_find_goal()is modified to choose a goal <UINT_MAX, so that our starting point is in an acceptable range.*
ext4_xattr_block_set()is modified such that the goal block is <UINT_MAX, as above.
Using UINT_MAX probably isn't wholly safe, as I know of systems that have e.g. 64-bit ints (though I guess none that have Linux kernel ports). It should use (u32)~0 or ((1 << 32) - 1) directly.
Quoted 1 line
Perhaps an ext4-specific #define would be better than
UINT_MAX?
I think yes, since we know the maximum value is tied specifically to the u32 indirect block pointers, and not necessarily to an "int".
Review
Quoted 6 lines
static
ext4_fsblk_text4_find_goal(struct inode *inode,ext4_lblk_tblock,
Indirect *partial)
{(quoted diff) +3
-0+ goal = ext4_find_near(inode, partial); + goal = goal % UINT_MAX; + return goal;
Using "% UINT_MAX" here will result in a 64-bit division on 32-bit platforms, since ext4_fsblk_t is declared as an unsigned long long. This should instead be "(u32)" or "& 0xffffffff".
Review ext4_mb_regular_allocator(struct ext4_allocation_context *ac) · line 1946
Quoted 5 lines
(quoted diff) +4
-0@@ -1943,6 +1943,11 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) + /* non-extent files are limited to low blocks/groups */ + if (!(EXT4_I(ac->ac_inode)->i_flags & EXT4_EXTENTS_FL)) + ngroups = min_t(unsigned long, ngroups, + (UINT_MAX / EXT4_BLOCKS_PER_GROUP(sb)));
Since EXT4_BLOCKS_PER_GROUP() is a run-time variable, but is constant for the life of the filesystem, this could be computed once and stored in the superblock?
Review inserted: · line 811
Quoted 4 lines
(quoted diff) +3
-0+++ b/fs/ext4/xattr.c@@ -810,12 +810,22 @@ inserted: + if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) + goal = goal % UINT_MAX;
As above.
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
Quoted 19 lines · Andreas Dilger
Quoted 7 lines · Eric Sandeen
Today, the ext4 allocator will happily allocate blocks past 232 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
This patch limits such allocations to < 2^32, and adds
WARN_ONs(maybe should beBUG_ONs) if we do get blocks larger than that.Eric, thanks for making the patch.
Quoted 7 lines
This should address RH Bug 519471, ext4 bitmap allocator must limit blocks to < 2^32
*
ext4_find_goal()is modified to choose a goal <UINT_MAX, so that our starting point is in an acceptable range.*
ext4_xattr_block_set()is modified such that the goal block is <UINT_MAX, as above.
Quoted 8 lines
Using
UINT_MAXprobably isn't wholly safe, as I know of systems that have e.g. 64-bit ints (though I guess none that have Linux kernel ports). It should use (u32)~0 or ((1 << 32) - 1) directly.Quoted 1 line
Perhaps an ext4-specific #define would be better than
UINT_MAX?I think yes, since we know the maximum value is tied specifically to the u32 indirect block pointers, and not necessarily to an "int".
yep, I had considered that, I should have just done it :) (esp considering the patch I sent a while back to get rid of similar things) :)
Quoted 10 lines
Review
Quoted 6 lines
static
ext4_fsblk_text4_find_goal(struct inode *inode,ext4_lblk_tblock,
Indirect *partial)
{(quoted diff) +3
-0+ goal = ext4_find_near(inode, partial); + goal = goal % UINT_MAX; + return goal;Using "%
UINT_MAX" here will result in a 64-bit division on 32-bit platforms, sinceext4_fsblk_tis declared as an unsigned long long. This should instead be "(u32)" or "&0xffffffff".
whoops good point. I wasn't thinking of 32-bit boxes, thinking they can't go past 16T but for smaller blocks we still could go past 2^32 blocks... and it is a 64-bit modulo regardless.
Quoted 9 lines
Review ext4_mb_regular_allocator(struct ext4_allocation_context *ac) · line 1946
Quoted 5 lines
(quoted diff) +4
-0@@ -1943,6 +1943,11 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) + /* non-extent files are limited to low blocks/groups */ + if (!(EXT4_I(ac->ac_inode)->i_flags & EXT4_EXTENTS_FL)) + ngroups = min_t(unsigned long, ngroups, + (UINT_MAX / EXT4_BLOCKS_PER_GROUP(sb)));Since
EXT4_BLOCKS_PER_GROUP()is a run-time variable, but is constant for the life of the filesystem, this could be computed once and stored in the superblock?
ok.
Quoted 6 lines
Review inserted: · line 811
Quoted 4 lines
(quoted diff) +3
-0+++ b/fs/ext4/xattr.c@@ -810,12 +810,22 @@ inserted: + if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) + goal = goal % UINT_MAX;As above.
Thanks for the review, will fix those up.
-Eric
Quoted 10 lines
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.--
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RFC PATCH v3 1/1 ext4: limit block allocations for indirect-block files to < 2^32
In reply to Andreas DilgerToday, the ext4 allocator will happily allocate blocks past 232 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
This patch limits such allocations to < 232, and adds WARN_ONs (maybe should be BUG_ONs) if we do get blocks larger than that.
This should address RH Bug 519471, ext4 bitmap allocator must limit blocks to < 232
* ext4_find_goal() is modified to choose a goal < UINT_MAX, so that our starting point is in an acceptable range.
* ext4_xattr_block_set() is modified such that the goal block is < UINT_MAX, as above.
* ext4_mb_regular_allocator() is modified so that the group search does not continue into groups which are too high
* ext4_mb_use_preallocated() has a check that we don't use preallocated space which is too far out
* ext4_alloc_blocks() and ext4_xattr_block_set() add some WARN_ONs
No attempt has been made to limit inode locations to < 232, so we may wind up with blocks far from their inodes. Doing this much already will lead to some odd ENOSPC issues when the "lower 32" gets full, and further restricting inodes could make that even weirder.
For high inodes, choosing a goal of the original, % UINT_MAX, may be a bit odd, but then we're in an odd situation anyway, and I don't know of a better heuristic.
Perhaps an ext4-specific #define would be better than UINT_MAX?
The allocator being what it is, I may have missed some spots, so I'd welcome review.
Thanks,
-Eric
---
V2: got modulo-happy in ext4_mb_regular_allocator, just limit ngroups to no more than UINT_MAX.
V3: address some of Andreas' review points
But I think we need some better macro & sb info member names...
fs/ext4/ext4.h +4 -0
@@ -386,6 +386,9 @@ struct ext4_mount_options {#endif }; +/* Max physical block we can addres w/o extents */ +#define EXT4_MAX_BLOCK_FILE_PHYS 0xFFFFFFFF +/* * Structure of an inode on the disk */
@@ -841,6 +844,7 @@ struct ext4_sb_info {unsigned long s_gdb_count;/* Number of group descriptor blocks */ unsigned long s_desc_per_block;/* Number of group descriptors per block */ ext4_group_t s_groups_count;/* Number of groups in the fs */ +ext4_group_t s_blockfile_groups;/* Groups acceptable for non-extent files */ unsigned long s_overhead_last;/* Last calculated overhead */ unsigned long s_blocks_last;/* Last seen block count */ loff_t s_bitmap_maxbytes;/* max bytes for bitmap files */
fs/ext4/inode.c +10 -1
@@ -551,15 +551,21 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)* * Normally this function find the preferred place for block allocation, * returns it. +* Because this is only used for non-extent files, we limit the block nr +* to 32 bits. */ static ext4_fsblk_t ext4_find_goal (struct inode *inode,ext4_lblk_t block,Indirect *partial) { +ext4_fsblk_t goal; +/* * XXX need to get goal block from mballoc's data structures */ -return ext4_find_near (inode, partial); + goal =ext4_find_near (inode, partial); + goal = goal &EXT4_MAX_BLOCK_FILE_PHYS ; +return goal; }/**
@@ -640,6 +646,8 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,if (*err) goto failed_out; +WARN_ON (current_block + count >EXT4_MAX_BLOCK_FILE_PHYS ); + target -= count;/* allocate blocks for indirect blocks */ while (index < indirect_blks && count) {
@@ -674,6 +682,7 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, ar.flags =EXT4_MB_HINT_DATA ; current_block =ext4_mb_new_blocks (handle, &ar, err); +WARN_ON (current_block + ar.len >EXT4_MAX_BLOCK_FILE_PHYS );if (*err && (target == blks)) {/*
fs/ext4/mballoc.c +9 -0
@@ -1943,6 +1943,10 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) sb = ac->ac_sb; sbi =EXT4_SB (sb); ngroups =ext4_get_groups_count (sb); +/* non-extent files are limited to low blocks/groups */ +if (!(EXT4_I (ac->ac_inode)->i_flags &EXT4_EXTENTS_FL )) + ngroups = sbi->s_blockfile_groups; +BUG_ON (ac->ac_status ==AC_STATUS_FOUND );/* first, try the goal */
@@ -3382,6 +3386,11 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len)continue ; +/* non-extent files can't have physical blocks past 2^32 */ +if (!(EXT4_I (ac->ac_inode)->i_flags &EXT4_EXTENTS_FL ) && + pa->pa_pstart + pa->pa_len >EXT4_MAX_BLOCK_FILE_PHYS ) +continue ; +/* found preallocated blocks, use them */ spin_lock (&pa->pa_lock);if (pa->pa_deleted ==0 && pa->pa_free) {
fs/ext4/super.c +2 -0
@@ -2595,6 +2595,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount; } sbi->s_groups_count = blocks_count; + sbi->s_blockfile_groups =min_t (ext4_group_t, sbi->s_groups_count, + (EXT4_MAX_BLOCK_FILE_PHYS /EXT4_BLOCKS_PER_GROUP (sb))); db_count = (sbi->s_groups_count +EXT4_DESC_PER_BLOCK (sb) -1 ) /EXT4_DESC_PER_BLOCK (sb); sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
fs/ext4/xattr.c +13 -2
@@ -810,12 +810,23 @@ inserted:get_bh (new_bh); }else {/* We need to allocate a new block */ -ext4_fsblk_t goal =ext4_group_first_block_no (sb, +ext4_fsblk_t goal, block; + + goal =ext4_group_first_block_no (sb,EXT4_I (inode)->i_block_group); -ext4_fsblk_t block =ext4_new_meta_blocks (handle, inode, + +/* non-extent files can't have physical blocks past 2^32 */ +if (!(EXT4_I (inode)->i_flags &EXT4_EXTENTS_FL )) + goal = goal &EXT4_MAX_BLOCK_FILE_PHYS ; + + block =ext4_new_meta_blocks (handle, inode, goal,NULL , &error);if (error) goto cleanup; + +if (!(EXT4_I (inode)->i_flags &EXT4_EXTENTS_FL )) +WARN_ON (block >EXT4_MAX_BLOCK_FILE_PHYS ); +ea_idebug (inode,"creating block %d" , block); new_bh =sb_getblk (sb, block);
Theodore Tso
maintainerQuoted 3 lines · Eric Sandeen
Today, the ext4 allocator will happily allocate blocks past 232 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
Everywhere where you say 232, you mean 2^32, right?
- Ted
Quoted 6 lines · Theodore Tso
Quoted 3 lines · Eric Sandeen
Today, the ext4 allocator will happily allocate blocks past 232 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
Everywhere where you say 232, you mean 2^32, right?
sorry, cut and paste error, yes.
(email client helpfully turned 2^32 into something prettier, but then didn't copy it right on the resend)
-Eric
Quoted 3 lines · Eric Sandeen
This patch limits such allocations to < 232, and adds
WARN_ONs(maybe should beBUG_ONs) if we do get blocks larger than that.
Given that this may corrupt the filesystem (e.g. block 2^32 turning into block 0 and overwriting the superblock) I think a BUG_ON() is probably more appropriate. This should only happen with software bugs, so it is more appropriate than ext4_error() I think.
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
Quoted 10 lines · Andreas Dilger
Quoted 3 lines · Eric Sandeen
This patch limits such allocations to < 232, and adds
WARN_ONs(maybe should beBUG_ONs) if we do get blocks larger than that.Given that this may corrupt the filesystem (e.g. block 2^32 turning into block 0 and overwriting the superblock) I think a
BUG_ON()is probably more appropriate. This should only happen with software bugs, so it is more appropriate thanext4_error()I think.
Ok, fine by me. I can send an update.
Any suggestions on the naming issues? (what's the official name for a "not-extent-based-file?")
I ran it a lot through a mkfs/mount/fsstress/unmount/fsck cycle, and all seemed well. mkfs was without extents, so I was thinking we were in good shape.
However, Ric just ran a massive fs_mark test on a 60T filesystem that he created with "mke2fs" (no extents and no journal - accidentally) and we got no corruption even without this patch.
I need to see if a filesystem w/o the extents feature (at all, vs. some old-format files on an extents fs) never even tries to allocate past 2^32; I didn't think so, but now not so sure.
I probably need to do more testing ...
-Eric
Theodore Tso
maintainerQuoted 4 lines · Eric Sandeen
Ok, fine by me. I can send an update.
Any suggestions on the naming issues? (what's the official name for a "not-extent-based-file?")
What I normally use is "extent-mapped file" and "indirect block mapped file", or "non-extent-mapped file".
- Ted
Quoted 8 lines · Theodore Tso
Quoted 4 lines · Eric Sandeen
Ok, fine by me. I can send an update.
Any suggestions on the naming issues? (what's the official name for a "not-extent-based-file?")
What I normally use is "extent-mapped file" and "indirect block mapped file", or "non-extent-mapped file".
I'll see if that can fit in a macro name nicely :)
Thanks,
-Eric
Quoted 1 line
- Ted
Quoted 2 lines · Eric Sandeen
Any suggestions on the naming issues? (what's the official name for a "not-extent-based-file?")
I've always used "block mapped" (i.e. mapped block-by-block) vs. "extent mapped".
Quoted 7 lines
However, Ric just ran a massive
fs_marktest on a 60T filesystem that he created with "mke2fs" (no extents and no journal - accidentally) and we got no corruption even without this patch.I need to see if a filesystem w/o the extents feature (at all, vs. some old-format files on an extents fs) never even tries to allocate past 2^32; I didn't think so, but now not so sure.
Well, it may depend a lot on which inodes are in use. That will set the goal block, and may prevent any above-16TB allocations. Either you could fill the bitmaps with 0xff (and zero the free blocks counters, to avoid problems with mballoc), or actually fill the first 16TB of the filesystem.
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
Quoted 11 lines · Andreas Dilger
Quoted 2 lines · Eric Sandeen
Any suggestions on the naming issues? (what's the official name for a "not-extent-based-file?")
I've always used "block mapped" (i.e. mapped block-by-block) vs. "extent mapped".
Quoted 4 lines
However, Ric just ran a massive
fs_marktest on a 60T filesystem that he created with "mke2fs" (no extents and no journal - accidentally) and we got no corruption even without this patch.
Quoted 6 lines
Quoted 3 lines
I need to see if a filesystem w/o the extents feature (at all, vs. some old-format files on an extents fs) never even tries to allocate past 2^32; I didn't think so, but now not so sure.
Well, it may depend a lot on which inodes are in use. That will set the goal block, and may prevent any above-16TB allocations. Either you could
yep, though I had many, many inodes in the high groups ...
Problem is I don't quite trust debugfs etc to get it right, so when I see < 32 bits, I'm not sure if it's really there, or if the reporting/debug tool wrapped it ;)
-Eric
Quoted 4 lines · Andreas Dilger
Well, it may depend a lot on which inodes are in use. That will set the goal block, and may prevent any above-16TB allocations. Either you could fill the bitmaps with
0xff(and zero the free blocks counters, to avoid problems with mballoc), or actually fill the first 16TB of the filesystem.
Or, just start creating top-level directories until you get one past 16TB and use that for your test... We have a patch for allowing a goal inode to be specified, and it might make sense to add a mount option to allow setting the inode goal for testing...
Hey, look, I even posted that patch, I now recall:
http://osdir.com/ml/linux-ext4/2009-06/msg00233.html
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.
Theodore Tso
maintainerQuoted 4 lines · Eric Sandeen
Problem is I don't quite trust debugfs etc to get it right, so when I see < 32 bits, I'm not sure if it's really there, or if the reporting/debug tool wrapped it ;)
Debugfs from pu branch definitely does get it right --- I've checked.
- Ted
Quoted 8 lines · Theodore Tso
Quoted 3 lines · Eric Sandeen
Problem is I don't quite trust debugfs etc to get it right, so when I see < 32 bits, I'm not sure if it's really there, or if the reporting/debug tool wrapped it ;)
Debugfs from pu branch definitely does get it right --- I've checked.
- Ted
I couldn't get debugfs from pu to even load a large filesystem, odd...
# debugfs/debugfs ../bigfile debugfs 1.41.9 (22-Aug-2009) ../bigfile: Filesystem too large to use legacy bitmaps while reading block bitmap
I haven't yet looked into this...
-Eric
RFC PATCH v4 1/1 ext4: limit block allocations for indirect-block files to < 2^32
In reply to Eric SandeenToday, the ext4 allocator will happily allocate blocks past 2^32 for indirect-block files, which results in the block numbers getting truncated, and corruption ensues.
This patch limits such allocations to < 2^32, and adds BUG_ONs if we do get blocks larger than that.
This should address RH Bug 519471, ext4 bitmap allocator must limit blocks to < 2^32
* ext4_find_goal() is modified to choose a goal < UINT_MAX, so that our starting point is in an acceptable range.
* ext4_xattr_block_set() is modified such that the goal block is < UINT_MAX, as above.
* ext4_mb_regular_allocator() is modified so that the group search does not continue into groups which are too high
* ext4_mb_use_preallocated() has a check that we don't use preallocated space which is too far out
* ext4_alloc_blocks() and ext4_xattr_block_set() add some BUG_ONs
No attempt has been made to limit inode locations to < 2^32, so we may wind up with blocks far from their inodes. Doing this much already will lead to some odd ENOSPC issues when the "lower 32" gets full, and further restricting inodes could make that even weirder.
For high inodes, choosing a goal of the original, % UINT_MAX, may be a bit odd, but then we're in an odd situation anyway, and I don't know of a better heuristic.
The allocator being what it is, I may have missed some spots, so I'd welcome review.
Thanks,
-Eric
---
V2: got modulo-happy in ext4_mb_regular_allocator, just limit ngroups to no more than UINT_MAX.
V3: address some of Andreas' review points
But I think we need some better macro & sb info member names...
V4: Change to BUG_ONs per Andreas's further review
fs/ext4/ext4.h +4 -0
@@ -386,6 +386,9 @@ struct ext4_mount_options {#endif }; +/* Max physical block we can addres w/o extents */ +#define EXT4_MAX_BLOCK_FILE_PHYS 0xFFFFFFFF +/* * Structure of an inode on the disk */
@@ -841,6 +844,7 @@ struct ext4_sb_info {unsigned long s_gdb_count;/* Number of group descriptor blocks */ unsigned long s_desc_per_block;/* Number of group descriptors per block */ ext4_group_t s_groups_count;/* Number of groups in the fs */ +ext4_group_t s_blockfile_groups;/* Groups acceptable for non-extent files */ unsigned long s_overhead_last;/* Last calculated overhead */ unsigned long s_blocks_last;/* Last seen block count */ loff_t s_bitmap_maxbytes;/* max bytes for bitmap files */
fs/ext4/inode.c +10 -1
@@ -551,15 +551,21 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)* * Normally this function find the preferred place for block allocation, * returns it. +* Because this is only used for non-extent files, we limit the block nr +* to 32 bits. */ static ext4_fsblk_t ext4_find_goal (struct inode *inode,ext4_lblk_t block,Indirect *partial) { +ext4_fsblk_t goal; +/* * XXX need to get goal block from mballoc's data structures */ -return ext4_find_near (inode, partial); + goal =ext4_find_near (inode, partial); + goal = goal &EXT4_MAX_BLOCK_FILE_PHYS ; +return goal; }/**
@@ -640,6 +646,8 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,if (*err) goto failed_out; +BUG_ON (current_block + count >EXT4_MAX_BLOCK_FILE_PHYS ); + target -= count;/* allocate blocks for indirect blocks */ while (index < indirect_blks && count) {
@@ -674,6 +682,7 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, ar.flags =EXT4_MB_HINT_DATA ; current_block =ext4_mb_new_blocks (handle, &ar, err); +BUG_ON (current_block + ar.len >EXT4_MAX_BLOCK_FILE_PHYS );if (*err && (target == blks)) {/*
fs/ext4/mballoc.c +9 -0
@@ -1943,6 +1943,10 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) sb = ac->ac_sb; sbi =EXT4_SB (sb); ngroups =ext4_get_groups_count (sb); +/* non-extent files are limited to low blocks/groups */ +if (!(EXT4_I (ac->ac_inode)->i_flags &EXT4_EXTENTS_FL )) + ngroups = sbi->s_blockfile_groups; +BUG_ON (ac->ac_status ==AC_STATUS_FOUND );/* first, try the goal */
@@ -3382,6 +3386,11 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len)continue ; +/* non-extent files can't have physical blocks past 2^32 */ +if (!(EXT4_I (ac->ac_inode)->i_flags &EXT4_EXTENTS_FL ) && + pa->pa_pstart + pa->pa_len >EXT4_MAX_BLOCK_FILE_PHYS ) +continue ; +/* found preallocated blocks, use them */ spin_lock (&pa->pa_lock);if (pa->pa_deleted ==0 && pa->pa_free) {
fs/ext4/super.c +2 -0
@@ -2595,6 +2595,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount; } sbi->s_groups_count = blocks_count; + sbi->s_blockfile_groups =min_t (ext4_group_t, sbi->s_groups_count, + (EXT4_MAX_BLOCK_FILE_PHYS /EXT4_BLOCKS_PER_GROUP (sb))); db_count = (sbi->s_groups_count +EXT4_DESC_PER_BLOCK (sb) -1 ) /EXT4_DESC_PER_BLOCK (sb); sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
fs/ext4/xattr.c +13 -2
@@ -810,12 +810,23 @@ inserted:get_bh (new_bh); }else {/* We need to allocate a new block */ -ext4_fsblk_t goal =ext4_group_first_block_no (sb, +ext4_fsblk_t goal, block; + + goal =ext4_group_first_block_no (sb,EXT4_I (inode)->i_block_group); -ext4_fsblk_t block =ext4_new_meta_blocks (handle, inode, + +/* non-extent files can't have physical blocks past 2^32 */ +if (!(EXT4_I (inode)->i_flags &EXT4_EXTENTS_FL )) + goal = goal &EXT4_MAX_BLOCK_FILE_PHYS ; + + block =ext4_new_meta_blocks (handle, inode, goal,NULL , &error);if (error) goto cleanup; + +if (!(EXT4_I (inode)->i_flags &EXT4_EXTENTS_FL )) +BUG_ON (block >EXT4_MAX_BLOCK_FILE_PHYS ); +ea_idebug (inode,"creating block %d" , block); new_bh =sb_getblk (sb, block);
Theodore Tso
maintainerAdded to the ext4 patch queue, thanks.
- Ted