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authorJan Kara <jack@suse.cz>2007-06-16 17:16:14 (GMT)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-16 20:16:16 (GMT)
commit74584ae509befc2ed711810e7df4b075473869b2 (patch)
tree9cb1b4a06b8583895c96d9b1a959d81df3950a06 /fs
parent4b356be019d0c28f67af02809df7072c1c8f7d32 (diff)
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 <jack@suse.cz> Cc: Eric Sandeen <sandeen@sandeen.net> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/udf/inode.c11
-rw-r--r--fs/udf/truncate.c79
-rw-r--r--fs/udf/udfdecl.h1
3 files changed, 74 insertions, 17 deletions
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 1f01294..bf7de0b 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 77975ae..60d2776 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 67ded28..f581f2f 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 *);

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