Commit c278bfec authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o

ext4: Make ext4_get_blocks_wrap take the truncate_mutex early.

When doing a migrate from ext3 to ext4 inode we need to make sure the test
for inode type and walking inode data happens inside  lock. To make this
happen move truncate_mutex early before checking the i_flags.


This actually should enable us to remove the verify_chain().
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
parent 01f4adc0
......@@ -2129,6 +2129,10 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
return err ? err : allocated;
}
/*
* Need to be called with
* mutex_lock(&EXT4_I(inode)->truncate_mutex);
*/
int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock,
unsigned long max_blocks, struct buffer_head *bh_result,
......@@ -2144,7 +2148,6 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
__clear_bit(BH_New, &bh_result->b_state);
ext_debug("blocks %u/%lu requested for inode %u\n",
iblock, max_blocks, inode->i_ino);
mutex_lock(&EXT4_I(inode)->truncate_mutex);
/* check in cache */
goal = ext4_ext_in_cache(inode, iblock, &newex);
......@@ -2318,8 +2321,6 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
ext4_ext_drop_refs(path);
kfree(path);
}
mutex_unlock(&EXT4_I(inode)->truncate_mutex);
return err ? err : allocated;
}
......@@ -2449,6 +2450,7 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
* modify 1 super block, 1 block bitmap and 1 group descriptor.
*/
credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
mutex_lock(&EXT4_I(inode)->truncate_mutex)
retry:
while (ret >= 0 && ret < max_blocks) {
block = block + ret;
......@@ -2505,6 +2507,7 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
mutex_unlock(&EXT4_I(inode)->truncate_mutex)
/*
* Time to update the file size.
* Update only when preallocation was requested beyond the file size.
......
......@@ -243,13 +243,6 @@ static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
p->bh = bh;
}
static int verify_chain(Indirect *from, Indirect *to)
{
while (from <= to && from->key == *from->p)
from++;
return (from > to);
}
/**
* ext4_block_to_path - parse the block number into array of offsets
* @inode: inode in question (we are only interested in its superblock)
......@@ -348,10 +341,11 @@ static int ext4_block_to_path(struct inode *inode,
* (pointer to last triple returned, *@err == 0)
* or when it gets an IO error reading an indirect block
* (ditto, *@err == -EIO)
* or when it notices that chain had been changed while it was reading
* (ditto, *@err == -EAGAIN)
* or when it reads all @depth-1 indirect blocks successfully and finds
* the whole chain, all way to the data (returns %NULL, *err == 0).
*
* Need to be called with
* mutex_lock(&EXT4_I(inode)->truncate_mutex)
*/
static Indirect *ext4_get_branch(struct inode *inode, int depth,
ext4_lblk_t *offsets,
......@@ -370,9 +364,6 @@ static Indirect *ext4_get_branch(struct inode *inode, int depth,
bh = sb_bread(sb, le32_to_cpu(p->key));
if (!bh)
goto failure;
/* Reader: pointers */
if (!verify_chain(chain, p))
goto changed;
add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
/* Reader: end */
if (!p->key)
......@@ -380,10 +371,6 @@ static Indirect *ext4_get_branch(struct inode *inode, int depth,
}
return NULL;
changed:
brelse(bh);
*err = -EAGAIN;
goto no_block;
failure:
*err = -EIO;
no_block:
......@@ -787,6 +774,10 @@ static int ext4_splice_branch(handle_t *handle, struct inode *inode,
* return > 0, # of blocks mapped or allocated.
* return = 0, if plain lookup failed.
* return < 0, error case.
*
*
* Need to be called with
* mutex_lock(&EXT4_I(inode)->truncate_mutex)
*/
int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock, unsigned long maxblocks,
......@@ -825,18 +816,6 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
while (count < maxblocks && count <= blocks_to_boundary) {
ext4_fsblk_t blk;
if (!verify_chain(chain, partial)) {
/*
* Indirect block might be removed by
* truncate while we were reading it.
* Handling of that case: forget what we've
* got now. Flag the err as EAGAIN, so it
* will reread.
*/
err = -EAGAIN;
count = 0;
break;
}
blk = le32_to_cpu(*(chain[depth-1].p + count));
if (blk == first_block + count)
......@@ -844,44 +823,13 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
else
break;
}
if (err != -EAGAIN)
goto got_it;
goto got_it;
}
/* Next simple case - plain lookup or failed read of indirect block */
if (!create || err == -EIO)
goto cleanup;
mutex_lock(&ei->truncate_mutex);
/*
* If the indirect block is missing while we are reading
* the chain(ext4_get_branch() returns -EAGAIN err), or
* if the chain has been changed after we grab the semaphore,
* (either because another process truncated this branch, or
* another get_block allocated this branch) re-grab the chain to see if
* the request block has been allocated or not.
*
* Since we already block the truncate/other get_block
* at this point, we will have the current copy of the chain when we
* splice the branch into the tree.
*/
if (err == -EAGAIN || !verify_chain(chain, partial)) {
while (partial > chain) {
brelse(partial->bh);
partial--;
}
partial = ext4_get_branch(inode, depth, offsets, chain, &err);
if (!partial) {
count++;
mutex_unlock(&ei->truncate_mutex);
if (err)
goto cleanup;
clear_buffer_new(bh_result);
goto got_it;
}
}
/*
* Okay, we need to do block allocation. Lazily initialize the block
* allocation info here if necessary
......@@ -923,7 +871,6 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
*/
if (!err && extend_disksize && inode->i_size > ei->i_disksize)
ei->i_disksize = inode->i_size;
mutex_unlock(&ei->truncate_mutex);
if (err)
goto cleanup;
......
......@@ -1113,6 +1113,7 @@ ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
int create, int extend_disksize)
{
int retval;
mutex_lock(&EXT4_I(inode)->truncate_mutex);
if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
retval = ext4_ext_get_blocks(handle, inode,
(ext4_lblk_t)block, max_blocks,
......@@ -1122,6 +1123,7 @@ ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
(ext4_lblk_t)block, max_blocks,
bh, create, extend_disksize);
}
mutex_unlock(&EXT4_I(inode)->truncate_mutex);
return retval;
}
......
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