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udf: Allocate name buffer in directory iterator on heap

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Currently we allocate name buffer in directory iterators (struct
udf_fileident_iter) on stack. These structures are relatively large
(some 360 bytes on 64-bit architectures). For udf_rename() which needs
to keep three of these structures in parallel the stack usage becomes
rather heavy - 1536 bytes in total. Allocate the name buffer in the
iterator from heap to avoid excessive stack usage.

Link: https://lore.kernel.org/all/202212200558.lK9x1KW0-lkp@intel.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2022-12-20 12:38:45 +01:00
parent 19fd80de0a
commit 0aba4860b0
2 changed files with 16 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
fs/udf/directory.c
View File

@ -248,9 +248,14 @@ int udf_fiiter_init(struct udf_fileident_iter *iter, struct inode *dir,
iter->elen = 0;
iter->epos.bh = NULL;
iter->name = NULL;
iter->namebuf = kmalloc(UDF_NAME_LEN_CS0, GFP_KERNEL);
if (!iter->namebuf)
return -ENOMEM;
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
return udf_copy_fi(iter);
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
err = udf_copy_fi(iter);
goto out;
}
if (inode_bmap(dir, iter->pos >> dir->i_blkbits, &iter->epos,
&iter->eloc, &iter->elen, &iter->loffset) !=
@ -260,18 +265,18 @@ int udf_fiiter_init(struct udf_fileident_iter *iter, struct inode *dir,
udf_err(dir->i_sb,
"position %llu not allocated in directory (ino %lu)\n",
(unsigned long long)pos, dir->i_ino);
return -EFSCORRUPTED;
err = -EFSCORRUPTED;
goto out;
}
err = udf_fiiter_load_bhs(iter);
if (err < 0)
return err;
goto out;
err = udf_copy_fi(iter);
if (err < 0) {
out:
if (err < 0)
udf_fiiter_release(iter);
return err;
}
return 0;
}
int udf_fiiter_advance(struct udf_fileident_iter *iter)
{
@ -307,6 +312,8 @@ void udf_fiiter_release(struct udf_fileident_iter *iter)
brelse(iter->bh[0]);
brelse(iter->bh[1]);
iter->bh[0] = iter->bh[1] = NULL;
kfree(iter->namebuf);
iter->namebuf = NULL;
}
static void udf_copy_to_bufs(void *buf1, int len1, void *buf2, int len2,

2
fs/udf/udfdecl.h
View File

@ -99,7 +99,7 @@ struct udf_fileident_iter {
struct extent_position epos; /* Position after the above extent */
struct fileIdentDesc fi; /* Copied directory entry */
uint8_t *name; /* Pointer to entry name */
uint8_t namebuf[UDF_NAME_LEN_CS0]; /* Storage for entry name in case
uint8_t *namebuf; /* Storage for entry name in case
* the name is split between two blocks
*/
};