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  1. 26 May, 2011 8 commits
    • Sage Weil's avatar
      vfs: remove dget() from dentry_unhash() · 64252c75
      Sage Weil authored 
      This serves no useful purpose that I can discern.  All callers (rename,
rmdir) hold their own reference to the dentry.

A quick audit of all file systems showed no relevant checks on the value
of d_count in vfs_rmdir/vfs_rename_dir paths.
Signed-off-by: default avatarSage Weil <sage@newdream.net>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      64252c75
    • Sage Weil's avatar
      vfs: dentry_unhash immediately prior to rmdir · 48293699
      Sage Weil authored 
      This presumes that there is no reason to unhash a dentry if we fail because
it is a mountpoint or the LSM check fails, and that the LSM checks do not
depend on the dentry being unhashed.
Signed-off-by: default avatarSage Weil <sage@newdream.net>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      48293699
    • Jan Kara's avatar
      vfs: Block mmapped writes while the fs is frozen · ea13a864
      Jan Kara authored 
      We should not allow file modification via mmap while the filesystem is
frozen. So block in block_page_mkwrite() while the filesystem is frozen.
We cannot do the blocking wait in __block_page_mkwrite() since e.g. ext4
will want to call that function with transaction started in some cases
and that would deadlock. But we can at least do the non-blocking reliable
check in __block_page_mkwrite() which is the hardest part anyway.

We have to check for frozen filesystem with the page marked dirty and under
page lock with which we then return from ->page_mkwrite(). Only that way we
cannot race with writeback done by freezing code - either we mark the page
dirty after the writeback has started, see freezing in progress and block, or
writeback will wait for our page lock which is released only when the fault is
done and then writeback will writeout and writeprotect the page again.
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      ea13a864
    • Jan Kara's avatar
      vfs: Create __block_page_mkwrite() helper passing error values back · 24da4fab
      Jan Kara authored 
      Create __block_page_mkwrite() helper which does all what block_page_mkwrite()
does except that it passes back errors from __block_write_begin /
block_commit_write calls.
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      24da4fab
    • Roman Borisov's avatar
      fs/namespace.c: bound mount propagation fix · 7c6e984d
      Roman Borisov authored 
      This issue was discovered by users of busybox.  And the bug is actual for
busybox users, I don't know how it affects others.  Apparently, mount is
called with and without MS_SILENT, and this affects mount() behaviour.
But MS_SILENT is only supposed to affect kernel logging verbosity.

The following script was run in an empty test directory:

mkdir -p mount.dir mount.shared1 mount.shared2
touch mount.dir/a mount.dir/b
mount -vv --bind         mount.shared1 mount.shared1
mount -vv --make-rshared mount.shared1
mount -vv --bind         mount.shared2 mount.shared2
mount -vv --make-rshared mount.shared2
mount -vv --bind mount.shared2 mount.shared1
mount -vv --bind mount.dir     mount.shared2
ls -R mount.dir mount.shared1 mount.shared2
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
rm -f mount.dir/a mount.dir/b mount.dir/c
rmdir mount.dir mount.shared1 mount.shared2

mount -vv was used to show the mount() call arguments and result.
Output shows that flag argument has 0x00008000 = MS_SILENT bit:

mount: mount('mount.shared1','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared1','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared2','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared2','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('mount.dir','mount.shared2','(null)',0x00009000,'(null)'):0
mount.dir:
a
b

mount.shared1:

mount.shared2:
a
b

After adding --loud option to remove MS_SILENT bit from just one mount cmd:

mkdir -p mount.dir mount.shared1 mount.shared2
touch mount.dir/a mount.dir/b
mount -vv --bind         mount.shared1 mount.shared1 2>&1
mount -vv --make-rshared mount.shared1               2>&1
mount -vv --bind         mount.shared2 mount.shared2 2>&1
mount -vv --loud --make-rshared mount.shared2               2>&1  # <-HERE
mount -vv --bind mount.shared2 mount.shared1         2>&1
mount -vv --bind mount.dir     mount.shared2         2>&1
ls -R mount.dir mount.shared1 mount.shared2      2>&1
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
rm -f mount.dir/a mount.dir/b mount.dir/c
rmdir mount.dir mount.shared1 mount.shared2

The result is different now - look closely at mount.shared1 directory listing.
Now it does show files 'a' and 'b':

mount: mount('mount.shared1','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared1','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared2','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared2','',0x00104000,''):0
mount: mount('mount.shared2','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('mount.dir','mount.shared2','(null)',0x00009000,'(null)'):0

mount.dir:
a
b

mount.shared1:
a
b

mount.shared2:
a
b

The analysis shows that MS_SILENT flag which is ON by default in any
busybox-> mount operations cames to flags_to_propagation_type function and
causes the error return while is_power_of_2 checking because the function
expects only one bit set.  This doesn't allow to do busybox->mount with
any --make-[r]shared, --make-[r]private etc options.

Moreover, the recently added flags_to_propagation_type() function doesn't
allow us to do such operations as --make-[r]private --make-[r]shared etc.
when MS_SILENT is on.  The idea or clearing the MS_SILENT flag came from
to Denys Vlasenko.
Signed-off-by: default avatarRoman Borisov <ext-roman.borisov@nokia.com>
Reported-by: default avatarDenys Vlasenko <vda.linux@googlemail.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Cc: Alexander Shishkin <virtuoso@slind.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      7c6e984d
    • Jonas Gorski's avatar
      exportfs: reallow building as a module · 79fead47
      Jonas Gorski authored 
      Commit 990d6c2d ("vfs: Add name to file
handle conversion support") changed EXPORTFS to be a bool.
This was needed for earlier revisions of the original patch, but the actual
commit put the code needing it into its own file that only gets compiled
when FHANDLE is selected which in turn selects EXPORTFS.
So EXPORTFS can be safely compiled as a module when not selecting FHANDLE.
Signed-off-by: default avatarJonas Gorski <jonas.gorski@gmail.com>
Acked-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      79fead47
    • Al Viro's avatar
      merge handle_reval_dot and nameidata_drop_rcu_last · 9f1fafee
      Al Viro authored 
      new helper: complete_walk().  Done on successful completion
of walk, drops out of RCU mode, does d_revalidate of final
result if that hadn't been done already.

handle_reval_dot() and nameidata_drop_rcu_last() subsumed into
that one; callers converted to use of complete_walk().
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      9f1fafee
    • Al Viro's avatar
      consolidate nameidata_..._drop_rcu() · 19660af7
      Al Viro authored 
      Merge these into a single function (unlazy_walk(nd, dentry)),
kill ..._maybe variants
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      19660af7
  3. 29 Apr, 2011 12 commits
  5. 28 Apr, 2011 18 commits
  7. 27 Apr, 2011 2 commits
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