From: Jan Kara Date: Sat, 16 Jun 2007 17:16:14 +0000 (-0700) Subject: udf: fix possible leakage of blocks X-Git-Tag: v2.6.22-rc5~3 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=74584ae509befc2ed711810e7df4b075473869b2;p=linux-2.6 udf: fix possible leakage of blocks We have to take care that when we call udf_discard_prealloc() from udf_clear_inode() we have to write inode ourselves afterwards (otherwise, some changes might be lost leading to leakage of blocks, use of free blocks or improperly aligned extents). Also udf_discard_prealloc() does two different things - it removes preallocated blocks and truncates the last extent to exactly match i_size. We move the latter functionality to udf_truncate_tail_extent(), call udf_discard_prealloc() when last reference to a file is dropped and call udf_truncate_tail_extent() when inode is being removed from inode cache (udf_clear_inode() call). We cannot call udf_truncate_tail_extent() earlier as subsequent open+write would find the last block of the file mapped and happily write to the end of it, although the last extent says it's shorter. [akpm@linux-foundation.org: Make checkpatch.pl happier] Signed-off-by: Jan Kara Cc: Eric Sandeen Cc: Cyrill Gorcunov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/udf/inode.c b/fs/udf/inode.c index 1f0129405c..bf7de0bdba 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -100,14 +100,23 @@ no_delete: clear_inode(inode); } +/* + * If we are going to release inode from memory, we discard preallocation and + * truncate last inode extent to proper length. We could use drop_inode() but + * it's called under inode_lock and thus we cannot mark inode dirty there. We + * use clear_inode() but we have to make sure to write inode as it's not written + * automatically. + */ void udf_clear_inode(struct inode *inode) { if (!(inode->i_sb->s_flags & MS_RDONLY)) { lock_kernel(); + /* Discard preallocation for directories, symlinks, etc. */ udf_discard_prealloc(inode); + udf_truncate_tail_extent(inode); unlock_kernel(); + write_inode_now(inode, 1); } - kfree(UDF_I_DATA(inode)); UDF_I_DATA(inode) = NULL; } diff --git a/fs/udf/truncate.c b/fs/udf/truncate.c index 77975ae291..60d2776442 100644 --- a/fs/udf/truncate.c +++ b/fs/udf/truncate.c @@ -61,7 +61,11 @@ static void extent_trunc(struct inode * inode, struct extent_position *epos, } } -void udf_discard_prealloc(struct inode * inode) +/* + * Truncate the last extent to match i_size. This function assumes + * that preallocation extent is already truncated. + */ +void udf_truncate_tail_extent(struct inode *inode) { struct extent_position epos = { NULL, 0, {0, 0}}; kernel_lb_addr eloc; @@ -71,7 +75,10 @@ void udf_discard_prealloc(struct inode * inode) int adsize; if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB || - inode->i_size == UDF_I_LENEXTENTS(inode)) + inode->i_size == UDF_I_LENEXTENTS(inode)) + return; + /* Are we going to delete the file anyway? */ + if (inode->i_nlink == 0) return; if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) @@ -79,36 +86,76 @@ void udf_discard_prealloc(struct inode * inode) else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) adsize = sizeof(long_ad); else - adsize = 0; - - epos.block = UDF_I_LOCATION(inode); + BUG(); /* Find the last extent in the file */ while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { etype = netype; lbcount += elen; - if (lbcount > inode->i_size && lbcount - elen < inode->i_size) - { - WARN_ON(lbcount - inode->i_size >= inode->i_sb->s_blocksize); + if (lbcount > inode->i_size) { + if (lbcount - inode->i_size >= inode->i_sb->s_blocksize) + printk(KERN_WARNING + "udf_truncate_tail_extent(): Too long " + "extent after EOF in inode %u: i_size: " + "%Ld lbcount: %Ld extent %u+%u\n", + (unsigned)inode->i_ino, + (long long)inode->i_size, + (long long)lbcount, + (unsigned)eloc.logicalBlockNum, + (unsigned)elen); nelen = elen - (lbcount - inode->i_size); epos.offset -= adsize; extent_trunc(inode, &epos, eloc, etype, elen, nelen); epos.offset += adsize; - lbcount = inode->i_size; + if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1) + printk(KERN_ERR "udf_truncate_tail_extent(): " + "Extent after EOF in inode %u.\n", + (unsigned)inode->i_ino); + break; } } + /* This inode entry is in-memory only and thus we don't have to mark + * the inode dirty */ + UDF_I_LENEXTENTS(inode) = inode->i_size; + brelse(epos.bh); +} + +void udf_discard_prealloc(struct inode *inode) +{ + struct extent_position epos = { NULL, 0, {0, 0}}; + kernel_lb_addr eloc; + uint32_t elen; + uint64_t lbcount = 0; + int8_t etype = -1, netype; + int adsize; + + if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB || + inode->i_size == UDF_I_LENEXTENTS(inode)) + return; + + if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT) + adsize = sizeof(short_ad); + else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG) + adsize = sizeof(long_ad); + else + adsize = 0; + + epos.block = UDF_I_LOCATION(inode); + + /* Find the last extent in the file */ + while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) { + etype = netype; + lbcount += elen; + } if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) { epos.offset -= adsize; lbcount -= elen; extent_trunc(inode, &epos, eloc, etype, elen, 0); - if (!epos.bh) - { + if (!epos.bh) { UDF_I_LENALLOC(inode) = epos.offset - udf_file_entry_alloc_offset(inode); mark_inode_dirty(inode); - } - else - { + } else { struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data); aed->lengthAllocDescs = cpu_to_le32(epos.offset - sizeof(struct allocExtDesc)); if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201) @@ -118,9 +165,9 @@ void udf_discard_prealloc(struct inode * inode) mark_buffer_dirty_inode(epos.bh, inode); } } + /* This inode entry is in-memory only and thus we don't have to mark + * the inode dirty */ UDF_I_LENEXTENTS(inode) = lbcount; - - WARN_ON(lbcount != inode->i_size); brelse(epos.bh); } diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h index 67ded28949..f581f2f69c 100644 --- a/fs/udf/udfdecl.h +++ b/fs/udf/udfdecl.h @@ -146,6 +146,7 @@ extern void udf_free_inode(struct inode *); extern struct inode * udf_new_inode (struct inode *, int, int *); /* truncate.c */ +extern void udf_truncate_tail_extent(struct inode *); extern void udf_discard_prealloc(struct inode *); extern void udf_truncate_extents(struct inode *);