ext4: make ext4_ext_get_blocks always return <= max_blocks
ext4_ext_get_blocks() returns number of blocks allocated with buffer heads unmapped for a read from prealloc space. This is needed so that delayed allocation doesn't do block reservation for prealloc space since the blocks are already resevred on disk. Fix ext4_ext_get_blocks to not return greater than max_blocks, since some of the code paths cannot handle such a return value. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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@ -2570,8 +2570,18 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
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}
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if (create == EXT4_CREATE_UNINITIALIZED_EXT)
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goto out;
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if (!create)
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if (!create) {
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/*
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* We have blocks reserved already. We
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* return allocated blocks so that delalloc
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* won't do block reservation for us. But
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* the buffer head will be unmapped so that
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* a read from the block returns 0s.
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*/
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if (allocated > max_blocks)
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allocated = max_blocks;
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goto out2;
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}
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ret = ext4_ext_convert_to_initialized(handle, inode,
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path, iblock,
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