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[PATCH] udf: initialize parts of inode earlier in create

I saw an oops down this path when trying to create a new file on a UDF
filesystem which was internally marked as readonly, but mounted rw:

udf_create
udf_new_inode
new_inode
alloc_inode
udf_alloc_inode
udf_new_block
returns EIO due to readonlyness
iput (on error)
udf_put_inode
udf_discard_prealloc
udf_next_aext
udf_current_aext
udf_get_fileshortad
OOPS

the udf_discard_prealloc() path was examining uninitialized fields of the
udf inode.

udf_discard_prealloc() already has this code to short-circuit the discard
path if no extents are preallocated:

if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
inode->i_size == UDF_I_LENEXTENTS(inode))
{
return;
}

so if we initialize UDF_I_LENEXTENTS(inode) = 0 earlier in udf_new_inode,
we won't try to free the (not) preallocated blocks, since this will match
the i_size = 0 set when the inode was initialized.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

authored by

Eric Sandeen and committed by
Linus Torvalds 225add61 ce2c6b53

+6 -5
+6 -5
fs/udf/ialloc.c
··· 75 75 } 76 76 *err = -ENOSPC; 77 77 78 + UDF_I_UNIQUE(inode) = 0; 79 + UDF_I_LENEXTENTS(inode) = 0; 80 + UDF_I_NEXT_ALLOC_BLOCK(inode) = 0; 81 + UDF_I_NEXT_ALLOC_GOAL(inode) = 0; 82 + UDF_I_STRAT4096(inode) = 0; 83 + 78 84 block = udf_new_block(dir->i_sb, NULL, UDF_I_LOCATION(dir).partitionReferenceNum, 79 85 start, err); 80 86 if (*err) ··· 90 84 } 91 85 92 86 mutex_lock(&sbi->s_alloc_mutex); 93 - UDF_I_UNIQUE(inode) = 0; 94 - UDF_I_LENEXTENTS(inode) = 0; 95 - UDF_I_NEXT_ALLOC_BLOCK(inode) = 0; 96 - UDF_I_NEXT_ALLOC_GOAL(inode) = 0; 97 - UDF_I_STRAT4096(inode) = 0; 98 87 if (UDF_SB_LVIDBH(sb)) 99 88 { 100 89 struct logicalVolHeaderDesc *lvhd;