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author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2008-01-29 04:58:27 (GMT) |
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committer | Theodore Ts'o <tytso@mit.edu> | 2008-01-29 04:58:27 (GMT) |
commit | c278bfecebfb1ed67c326ef472660878baa745cd (patch) | |
tree | 7207594cef5bd04ea7333a8321d78aefee01a540 /fs/ext4/inode.c | |
parent | 01f4adc04480a4e0395906d0268c056cf09c39c0 (diff) | |
download | linux-fsl-qoriq-c278bfecebfb1ed67c326ef472660878baa745cd.tar.xz |
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: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Diffstat (limited to 'fs/ext4/inode.c')
-rw-r--r-- | fs/ext4/inode.c | 69 |
1 files changed, 8 insertions, 61 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index eaace13..71c7ad0 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -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 @@ err_out: * 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; |