| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 29 Sep 2009 12:38:29 -0700
From: Jiaying Zhang <jiayingz@...gle.com>
To: Eric Sandeen <sandeen@...hat.com>
Cc: Andreas Dilger <adilger@....com>, Theodore Tso <tytso@....edu>,
Frank Mayhar <fmayhar@...gle.com>,
Curt Wohlgemuth <curtw@...gle.com>,
ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: Question on fallocate/ftruncate sequence
On Tue, Sep 29, 2009 at 12:15 PM, Eric Sandeen <sandeen@...hat.com> wrote:
> Jiaying Zhang wrote:
>> Sorry for taking so long to finish this. Here is the new patch based on
>> Andreas's suggestions. Now the patch clears the EXT4_EOFBLOCKS_FL
>> flag when we allocate beyond the maximum allocated block. I also
>> made the EOFBLOCKS flag user visible and added the handling
>> in ext4_ioctl as Andrea suggested.
>
> I was testing this a bit in xfstests, with test 083 (recently I sent a
> patch to the xfs list to let that test run on generic filesystems) which
> runs fsstress on a small-ish 100M fs, and that fsstress does space
> preallocation (on newer kernels, where the older xfs ioctls are hooked
> up to do_fallocate in a generic fashion).
Does the fsstress use fallocate with KEEP_SIZE?
>
> I'm actually seeing more corruption w/ this patch than without it,
> though I don't yet see why. I'll double check that it applied properly,
> since this was against 2.6.30.5....
Do you want me to port my changes to the latest ext4 git tree?
I should have done so at the beginning.
>
> Also it strikes me as a little odd to allow clearing of the EOF Flag
> from userspace, and the subsequent discarding of the blocks past EOF.
>
> Doesn't truncating to i_size do exactly the same thing, in a more
> portable way? Why make a new interface unique to ext4?
As Andreas suggested, I think the main purpose is to allow users
to scan for any files with EOF flag with the getflag ioctl. We may
not allow users to clear it with the setflag ioctl but just rely on
the truncate interface, but supporting the setflag ioctl interface
doesn't seem to do any harm.
Jiaying
>
> -Eric
>
>> Index: linux-2.6.30.5/fs/ext4/inode.c
>> ===================================================================
>> --- linux-2.6.30.5.orig/fs/ext4/inode.c 2009-08-31 12:08:10.000000000 -0700
>> +++ linux-2.6.30.5/fs/ext4/inode.c 2009-09-23 21:42:33.000000000 -0700
>> @@ -3973,6 +3973,8 @@ void ext4_truncate(struct inode *inode)
>> if (!ext4_can_truncate(inode))
>> return;
>>
>> + inode->i_flags &= ~EXT4_EOFBLOCKS_FL;
>> +
>> if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
>> ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
>>
>> @@ -4285,8 +4287,8 @@ void ext4_get_inode_flags(struct ext4_in
>> {
>> unsigned int flags = ei->vfs_inode.i_flags;
>>
>> - ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
>> - EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
>> + ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|EXT4_IMMUTABLE_FL|
>> + EXT4_NOATIME_FL|EXT4_DIRSYNC_FL|EXT4_EOFBLOCKS_FL);
>> if (flags & S_SYNC)
>> ei->i_flags |= EXT4_SYNC_FL;
>> if (flags & S_APPEND)
>> @@ -4297,6 +4299,8 @@ void ext4_get_inode_flags(struct ext4_in
>> ei->i_flags |= EXT4_NOATIME_FL;
>> if (flags & S_DIRSYNC)
>> ei->i_flags |= EXT4_DIRSYNC_FL;
>> + if (flags & FS_EOFBLOCKS_FL)
>> + ei->i_flags |= EXT4_EOFBLOCKS_FL;
>> }
>> static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
>> struct ext4_inode_info *ei)
>> @@ -4807,7 +4811,9 @@ int ext4_setattr(struct dentry *dentry,
>> }
>>
>> if (S_ISREG(inode->i_mode) &&
>> - attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
>> + attr->ia_valid & ATTR_SIZE &&
>> + (attr->ia_size < inode->i_size ||
>> + (inode->i_flags & EXT4_EOFBLOCKS_FL))) {
>> handle_t *handle;
>>
>> handle = ext4_journal_start(inode, 3);
>> @@ -4838,6 +4844,11 @@ int ext4_setattr(struct dentry *dentry,
>> goto err_out;
>> }
>> }
>> + if ((inode->i_flags & EXT4_EOFBLOCKS_FL)) {
>> + rc = vmtruncate(inode, attr->ia_size);
>> + if (rc)
>> + goto err_out;
>> + }
>> }
>>
>> rc = inode_setattr(inode, attr);
>> Index: linux-2.6.30.5/include/linux/fs.h
>> ===================================================================
>> --- linux-2.6.30.5.orig/include/linux/fs.h 2009-08-31
>> 12:08:10.000000000 -0700
>> +++ linux-2.6.30.5/include/linux/fs.h 2009-09-10 21:27:30.000000000 -0700
>> @@ -343,9 +343,10 @@ struct inodes_stat_t {
>> #define FS_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/
>> #define FS_EXTENT_FL 0x00080000 /* Extents */
>> #define FS_DIRECTIO_FL 0x00100000 /* Use direct i/o */
>> +#define FS_EOFBLOCKS_FL 0x00200000 /* Blocks allocated beyond EOF */
>> #define FS_RESERVED_FL 0x80000000 /* reserved for ext2 lib */
>>
>> -#define FS_FL_USER_VISIBLE 0x0003DFFF /* User visible flags */
>> +#define FS_FL_USER_VISIBLE 0x0023DFFF /* User visible flags */
>> #define FS_FL_USER_MODIFIABLE 0x000380FF /* User modifiable flags */
>>
>>
>> Index: linux-2.6.30.5/fs/ext4/ext4.h
>> ===================================================================
>> --- linux-2.6.30.5.orig/fs/ext4/ext4.h 2009-08-31 12:08:10.000000000 -0700
>> +++ linux-2.6.30.5/fs/ext4/ext4.h 2009-09-10 21:28:14.000000000 -0700
>> @@ -235,9 +235,10 @@ struct flex_groups {
>> #define EXT4_HUGE_FILE_FL 0x00040000 /* Set to each huge file */
>> #define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */
>> #define EXT4_EXT_MIGRATE 0x00100000 /* Inode is migrating */
>> +#define EXT4_EOFBLOCKS_FL 0x00200000 /* Blocks allocated
>> beyond EOF (bit reserved in fs.h) */
>> #define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */
>>
>> -#define EXT4_FL_USER_VISIBLE 0x000BDFFF /* User visible flags */
>> +#define EXT4_FL_USER_VISIBLE 0x002BDFFF /* User visible flags */
>> #define EXT4_FL_USER_MODIFIABLE 0x000B80FF /* User modifiable flags */
>>
>> /* Flags that should be inherited by new inodes from their parent. */
>> Index: linux-2.6.30.5/fs/ext4/extents.c
>> ===================================================================
>> --- linux-2.6.30.5.orig/fs/ext4/extents.c 2009-09-01 18:14:58.000000000 -0700
>> +++ linux-2.6.30.5/fs/ext4/extents.c 2009-09-23 22:12:22.000000000 -0700
>> @@ -2788,7 +2788,7 @@ int ext4_ext_get_blocks(handle_t *handle
>> {
>> struct ext4_ext_path *path = NULL;
>> struct ext4_extent_header *eh;
>> - struct ext4_extent newex, *ex;
>> + struct ext4_extent newex, *ex, *last_ex;
>> ext4_fsblk_t newblock;
>> int err = 0, depth, ret, cache_type;
>> unsigned int allocated = 0;
>> @@ -2968,6 +2968,14 @@ int ext4_ext_get_blocks(handle_t *handle
>> newex.ee_len = cpu_to_le16(ar.len);
>> if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */
>> ext4_ext_mark_uninitialized(&newex);
>> +
>> + if (unlikely(inode->i_flags & EXT4_EOFBLOCKS_FL)) {
>> + BUG_ON(!eh->eh_entries);
>> + last_ex = EXT_LAST_EXTENT(eh);
>> + if (iblock + ar.len > le32_to_cpu(last_ex->ee_block)
>> + + ext4_ext_get_actual_len(last_ex))
>> + inode->i_flags &= ~EXT4_EOFBLOCKS_FL;
>> + }
>> err = ext4_ext_insert_extent(handle, inode, path, &newex);
>> if (err) {
>> /* free data blocks we just allocated */
>> @@ -3095,6 +3103,13 @@ static void ext4_falloc_update_inode(str
>> i_size_write(inode, new_size);
>> if (new_size > EXT4_I(inode)->i_disksize)
>> ext4_update_i_disksize(inode, new_size);
>> + } else {
>> + /*
>> + * Mark that we allocate beyond EOF so the subsequent truncate
>> + * can proceed even if the new size is the same as i_size.
>> + */
>> + if (new_size > i_size_read(inode))
>> + inode->i_flags |= EXT4_EOFBLOCKS_FL;
>> }
>> }
>>
>> Index: linux-2.6.30.5/fs/ext4/ioctl.c
>> ===================================================================
>> --- linux-2.6.30.5.orig/fs/ext4/ioctl.c 2009-08-16 14:19:38.000000000 -0700
>> +++ linux-2.6.30.5/fs/ext4/ioctl.c 2009-09-23 22:04:47.000000000 -0700
>> @@ -92,6 +92,16 @@ long ext4_ioctl(struct file *filp, unsig
>> flags &= ~EXT4_EXTENTS_FL;
>> }
>>
>> + if (flags & EXT4_EOFBLOCKS_FL) {
>> + /* we don't support adding EOFBLOCKS flag */
>> + if (!(oldflags & EXT4_EOFBLOCKS_FL)) {
>> + err = -EOPNOTSUPP;
>> + goto flags_out;
>> + }
>> + } else if (oldflags & EXT4_EOFBLOCKS_FL)
>> + /* free the space reserved with fallocate KEEPSIZE */
>> + vmtruncate(inode, inode->i_size);
>> +
>> handle = ext4_journal_start(inode, 1);
>> if (IS_ERR(handle)) {
>> err = PTR_ERR(handle);
>>
>>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists