From: Steven J. Magnani steve.magnani@digidescorp.com
commit fa33cdbf3eceb0206a4f844fe91aeebcf6ff2b7a upstream.
In some cases, using the 'truncate' command to extend a UDF file results in a mismatch between the length of the file's extents (specifically, due to incorrect length of the final NOT_ALLOCATED extent) and the information (file) length. The discrepancy can prevent other operating systems (i.e., Windows 10) from opening the file.
Two particular errors have been observed when extending a file:
1. The final extent is larger than it should be, having been rounded up to a multiple of the block size.
B. The final extent is not shorter than it should be, due to not having been updated when the file's information length was increased.
[JK: simplified udf_do_extend_final_block(), fixed up some types]
Fixes: 2c948b3f86e5 ("udf: Avoid IO in udf_clear_inode") CC: stable@vger.kernel.org Signed-off-by: Steven J. Magnani steve@digidescorp.com Link: https://lore.kernel.org/r/1561948775-5878-1-git-send-email-steve@digidescorp... Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/udf/inode.c | 93 ++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 60 insertions(+), 33 deletions(-)
--- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -478,13 +478,15 @@ static struct buffer_head *udf_getblk(st return NULL; }
-/* Extend the file by 'blocks' blocks, return the number of extents added */ +/* Extend the file with new blocks totaling 'new_block_bytes', + * return the number of extents added + */ static int udf_do_extend_file(struct inode *inode, struct extent_position *last_pos, struct kernel_long_ad *last_ext, - sector_t blocks) + loff_t new_block_bytes) { - sector_t add; + uint32_t add; int count = 0, fake = !(last_ext->extLength & UDF_EXTENT_LENGTH_MASK); struct super_block *sb = inode->i_sb; struct kernel_lb_addr prealloc_loc = {}; @@ -494,7 +496,7 @@ static int udf_do_extend_file(struct ino
/* The previous extent is fake and we should not extend by anything * - there's nothing to do... */ - if (!blocks && fake) + if (!new_block_bytes && fake) return 0;
iinfo = UDF_I(inode); @@ -525,13 +527,12 @@ static int udf_do_extend_file(struct ino /* Can we merge with the previous extent? */ if ((last_ext->extLength & UDF_EXTENT_FLAG_MASK) == EXT_NOT_RECORDED_NOT_ALLOCATED) { - add = ((1 << 30) - sb->s_blocksize - - (last_ext->extLength & UDF_EXTENT_LENGTH_MASK)) >> - sb->s_blocksize_bits; - if (add > blocks) - add = blocks; - blocks -= add; - last_ext->extLength += add << sb->s_blocksize_bits; + add = (1 << 30) - sb->s_blocksize - + (last_ext->extLength & UDF_EXTENT_LENGTH_MASK); + if (add > new_block_bytes) + add = new_block_bytes; + new_block_bytes -= add; + last_ext->extLength += add; }
if (fake) { @@ -552,28 +553,27 @@ static int udf_do_extend_file(struct ino }
/* Managed to do everything necessary? */ - if (!blocks) + if (!new_block_bytes) goto out;
/* All further extents will be NOT_RECORDED_NOT_ALLOCATED */ last_ext->extLocation.logicalBlockNum = 0; last_ext->extLocation.partitionReferenceNum = 0; - add = (1 << (30-sb->s_blocksize_bits)) - 1; - last_ext->extLength = EXT_NOT_RECORDED_NOT_ALLOCATED | - (add << sb->s_blocksize_bits); + add = (1 << 30) - sb->s_blocksize; + last_ext->extLength = EXT_NOT_RECORDED_NOT_ALLOCATED | add;
/* Create enough extents to cover the whole hole */ - while (blocks > add) { - blocks -= add; + while (new_block_bytes > add) { + new_block_bytes -= add; err = udf_add_aext(inode, last_pos, &last_ext->extLocation, last_ext->extLength, 1); if (err) return err; count++; } - if (blocks) { + if (new_block_bytes) { last_ext->extLength = EXT_NOT_RECORDED_NOT_ALLOCATED | - (blocks << sb->s_blocksize_bits); + new_block_bytes; err = udf_add_aext(inode, last_pos, &last_ext->extLocation, last_ext->extLength, 1); if (err) @@ -604,6 +604,24 @@ out: return count; }
+/* Extend the final block of the file to final_block_len bytes */ +static void udf_do_extend_final_block(struct inode *inode, + struct extent_position *last_pos, + struct kernel_long_ad *last_ext, + uint32_t final_block_len) +{ + struct super_block *sb = inode->i_sb; + uint32_t added_bytes; + + added_bytes = final_block_len - + (last_ext->extLength & (sb->s_blocksize - 1)); + last_ext->extLength += added_bytes; + UDF_I(inode)->i_lenExtents += added_bytes; + + udf_write_aext(inode, last_pos, &last_ext->extLocation, + last_ext->extLength, 1); +} + static int udf_extend_file(struct inode *inode, loff_t newsize) {
@@ -613,10 +631,12 @@ static int udf_extend_file(struct inode int8_t etype; struct super_block *sb = inode->i_sb; sector_t first_block = newsize >> sb->s_blocksize_bits, offset; + unsigned long partial_final_block; int adsize; struct udf_inode_info *iinfo = UDF_I(inode); struct kernel_long_ad extent; - int err; + int err = 0; + int within_final_block;
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) adsize = sizeof(struct short_ad); @@ -626,18 +646,8 @@ static int udf_extend_file(struct inode BUG();
etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset); + within_final_block = (etype != -1);
- /* File has extent covering the new size (could happen when extending - * inside a block)? */ - if (etype != -1) - return 0; - if (newsize & (sb->s_blocksize - 1)) - offset++; - /* Extended file just to the boundary of the last file block? */ - if (offset == 0) - return 0; - - /* Truncate is extending the file by 'offset' blocks */ if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) || (epos.bh && epos.offset == sizeof(struct allocExtDesc))) { /* File has no extents at all or has empty last @@ -651,7 +661,22 @@ static int udf_extend_file(struct inode &extent.extLength, 0); extent.extLength |= etype << 30; } - err = udf_do_extend_file(inode, &epos, &extent, offset); + + partial_final_block = newsize & (sb->s_blocksize - 1); + + /* File has extent covering the new size (could happen when extending + * inside a block)? + */ + if (within_final_block) { + /* Extending file within the last file block */ + udf_do_extend_final_block(inode, &epos, &extent, + partial_final_block); + } else { + loff_t add = ((loff_t)offset << sb->s_blocksize_bits) | + partial_final_block; + err = udf_do_extend_file(inode, &epos, &extent, add); + } + if (err < 0) goto out; err = 0; @@ -756,6 +781,7 @@ static sector_t inode_getblk(struct inod /* Are we beyond EOF? */ if (etype == -1) { int ret; + loff_t hole_len; isBeyondEOF = true; if (count) { if (c) @@ -771,7 +797,8 @@ static sector_t inode_getblk(struct inod startnum = (offset > 0); } /* Create extents for the hole between EOF and offset */ - ret = udf_do_extend_file(inode, &prev_epos, laarr, offset); + hole_len = (loff_t)offset << inode->i_blkbits; + ret = udf_do_extend_file(inode, &prev_epos, laarr, hole_len); if (ret < 0) { brelse(prev_epos.bh); brelse(cur_epos.bh);