We need to make sure that existing ext3 filesystems can also avail the
new fields that have been added to the ext4 inode. We use
s_want_extra_isize and s_min_extra_isize to decide by how much we should
expand the inode. If EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE feature is set
then we expand the inode by max(s_want_extra_isize, s_min_extra_isize ,
sizeof(ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE) bytes. Actually it is
still an open question about whether users should be able to set
s_*_extra_isize smaller than the known fields or not.
This patch also adds the functionality to expand inodes to include the
newly added fields. We start by trying to expand by s_want_extra_isize
bytes and if its fails we try to expand by s_min_extra_isize bytes. This
is done by changing the i_extra_isize if enough space is available in
the inode and no EAs are present. If EAs are present and there is enough
space in the inode then the EAs in the inode are shifted to make space.
If enough space is not available in the inode due to the EAs then 1 or
more EAs are shifted to the external EA block. In the worst case when
even the external EA block does not have enough space we inform the user
that some EA would need to be deleted or s_min_extra_isize would have to
be reduced.
Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Kalpak Shah <kalpak@clusterfs.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This patch adds nanosecond timestamps for ext4. This involves adding
*time_extra fields to the ext4_inode to extend the timestamps to
64-bits. Creation time is also added by this patch.
These extended fields will fit into an inode if the filesystem was
formatted with large inodes (-I 256 or larger) and there are currently
no EAs consuming all of the available space. For new inodes we always
reserve enough space for the kernel's known extended fields, but for
inodes created with an old kernel this might not have been the case. So
this patch also adds the EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE feature
flag(ro-compat so that older kernels can't create inodes with a smaller
extra_isize). which indicates if the fields fitting inside
s_min_extra_isize are available or not. If the expansion of inodes if
unsuccessful then this feature will be disabled. This feature is only
enabled if requested by the sysadmin.
None of the extended inode fields is critical for correct filesystem
operation.
Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Kalpak Shah <kalpak@clusterfs.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
There are race issues around ext[34] xattr block release code.
ext[34]_xattr_release_block() checks the reference count of xattr block
(h_refcount) and frees that xattr block if it is the last one reference it.
Unlike ext2, the check of this counter is unprotected by any lock.
ext[34]_xattr_release_block() will free the mb_cache entry before freeing
that xattr block. There is a small window between the check for the re
h_refcount ==1 and the call to mb_cache_entry_free(). During this small
window another inode might find this xattr block from the mbcache and reuse
it, racing a refcount updates. The xattr block will later be freed by the
first inode without notice other inode is still use it. Later if that
block is reallocated as a datablock for other file, then more serious
problem might happen.
We need put a lock around places checking the refount as well to avoid
racing issue. Another place need this kind of protection is in
ext3_xattr_block_set(), where it will modify the xattr block content in-
the-fly if the refcount is 1 (means it's the only inode reference it).
This will also fix another issue: the xattr block may not get freed at all
if no lock is to protect the refcount check at the release time. It is
possible that the last two inodes could release the shared xattr block at
the same time. But both of them think they are not the last one so only
decreased the h_refcount without freeing xattr block at all.
We need to call lock_buffer() after ext3_journal_get_write_access() to
avoid deadlock (because the later will call lock_buffer()/unlock_buffer
() as well).
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lock_super() is unnecessary for setting super-block feature flags. Use the
provided *_SET_COMPAT_FEATURE() macros as well.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change ext4 in-kernel block type (ext4_fsblk_t) from sector_t to unsigned
long long. Remove ext4 block type string micro E3FSBLK, replaced with "%llu"
[akpm@osdl.org: build fix]
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Reworked from a patch by Mingming Cao and Randy Dunlap
Signed-off-By: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Mingming Cao originally did this work, and Shaggy reproduced it using some
scripts from her.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Start of the ext4 patch series. See Documentation/filesystems/ext4.txt for
details.
This is a simple copy of the files in fs/ext3 to fs/ext4 and
/usr/incude/linux/ext3* to /usr/include/ex4*
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
