Commit Graph

344 Commits

Author SHA1 Message Date
Tyler Hicks 3063287053 eCryptfs: Remove ecryptfs_header_cache_2
Now that ecryptfs_lookup_interpose() is no longer using
ecryptfs_header_cache_2 to read in metadata, the kmem_cache can be
removed and the ecryptfs_header_cache_1 kmem_cache can be renamed to
ecryptfs_header_cache.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-05-29 14:24:25 -05:00
Tyler Hicks 778aeb42a7 eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose()
ecryptfs_lookup_interpose() has turned into spaghetti code over the
years. This is an effort to clean it up.

 - Shorten overly descriptive variable names such as ecryptfs_dentry
 - Simplify gotos and error paths
 - Create helper function for reading plaintext i_size from metadata

It also includes an optimization when reading i_size from the metadata.
A complete page-sized kmem_cache_alloc() was being done to read in 16
bytes of metadata. The buffer for that is now statically declared.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-05-29 14:24:24 -05:00
Tyler Hicks 7a86617e55 eCryptfs: Return useful code from contains_ecryptfs_marker
Instead of having the calling functions translate the true/false return
code to either 0 or -EINVAL, have contains_ecryptfs_marker() return 0 or
-EINVAL so that the calling functions can just reuse the return code.

Also, rename the function to ecryptfs_validate_marker() to avoid callers
mistakenly thinking that it returns true/false codes.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-05-29 14:24:24 -05:00
Tyler Hicks 3b06b3ebf4 eCryptfs: Fix new inode race condition
Only unlock and d_add() new inodes after the plaintext inode size has
been read from the lower filesystem. This fixes a race condition that
was sometimes seen during a multi-job kernel build in an eCryptfs mount.

https://bugzilla.kernel.org/show_bug.cgi?id=36002

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Reported-by: David <david@unsolicited.net>
Tested-by: David <david@unsolicited.net>
2011-05-29 14:23:39 -05:00
Tyler Hicks 5ccf92037c eCryptfs: Cleanup inode initialization code
The eCryptfs inode get, initialization, and dentry interposition code
has two separate paths. One is for when dentry interposition is needed
after doing things like a mkdir in the lower filesystem and the other
is needed after a lookup. Unlocking new inodes and doing a d_add() needs
to happen at different times, depending on which type of dentry
interposing is being done.

This patch cleans up the inode get and initialization code paths and
splits them up so that the locking and d_add() differences mentioned
above can be handled appropriately in a later patch.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Tested-by: David <david@unsolicited.net>
2011-05-29 12:51:17 -05:00
Tyler Hicks c4f790736c eCryptfs: Consolidate inode functions into inode.c
These functions should live in inode.c since their focus is on inodes
and they're primarily used by functions in inode.c.

Also does a simple cleanup of ecryptfs_inode_test() and rolls
ecryptfs_init_inode() into ecryptfs_inode_set().

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Tested-by: David <david@unsolicited.net>
2011-05-29 12:49:53 -05:00
Linus Torvalds 36947a7682 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (36 commits)
  Cache xattr security drop check for write v2
  fs: block_page_mkwrite should wait for writeback to finish
  mm: Wait for writeback when grabbing pages to begin a write
  configfs: remove unnecessary dentry_unhash on rmdir, dir rename
  fat: remove unnecessary dentry_unhash on rmdir, dir rename
  hpfs: remove unnecessary dentry_unhash on rmdir, dir rename
  minix: remove unnecessary dentry_unhash on rmdir, dir rename
  fuse: remove unnecessary dentry_unhash on rmdir, dir rename
  coda: remove unnecessary dentry_unhash on rmdir, dir rename
  afs: remove unnecessary dentry_unhash on rmdir, dir rename
  affs: remove unnecessary dentry_unhash on rmdir, dir rename
  9p: remove unnecessary dentry_unhash on rmdir, dir rename
  ncpfs: fix rename over directory with dangling references
  ncpfs: document dentry_unhash usage
  ecryptfs: remove unnecessary dentry_unhash on rmdir, dir rename
  hostfs: remove unnecessary dentry_unhash on rmdir, dir rename
  hfsplus: remove unnecessary dentry_unhash on rmdir, dir rename
  hfs: remove unnecessary dentry_unhash on rmdir, dir rename
  omfs: remove unnecessary dentry_unhash on rmdir, dir rneame
  udf: remove unnecessary dentry_unhash from rmdir, dir rename
  ...
2011-05-28 13:03:41 -07:00
Sage Weil 55e5b7e022 ecryptfs: remove unnecessary dentry_unhash on rmdir, dir rename
ecryptfs does not have problems with references to unlinked directories.

CC: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
CC: Dustin Kirkland <kirkland@canonical.com>
CC: ecryptfs-devel@lists.launchpad.net
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-28 01:02:52 -04:00
Linus Torvalds aaab184276 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6:
  MAINTAINERS: Update eCryptfs mailing list
  eCryptfs: Allow 2 scatterlist entries for encrypted filenames
  eCryptfs: Clear i_nlink in rmdir
2011-05-27 11:07:50 -07:00
Tyler Hicks 8d08dab786 eCryptfs: Allow 2 scatterlist entries for encrypted filenames
The buffers allocated while encrypting and decrypting long filenames can
sometimes straddle two pages. In this situation, virt_to_scatterlist()
will return -ENOMEM, causing the operation to fail and the user will get
scary error messages in their logs:

kernel: ecryptfs_write_tag_70_packet: Internal error whilst attempting
to convert filename memory to scatterlist; expected rc = 1; got rc =
[-12]. block_aligned_filename_size = [272]
kernel: ecryptfs_encrypt_filename: Error attempting to generate tag 70
packet; rc = [-12]
kernel: ecryptfs_encrypt_and_encode_filename: Error attempting to
encrypt filename; rc = [-12]
kernel: ecryptfs_lookup: Error attempting to encrypt and encode
filename; rc = [-12]

The solution is to allow up to 2 scatterlist entries to be used.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
2011-05-27 11:46:14 -05:00
Tyler Hicks 07850552b9 eCryptfs: Clear i_nlink in rmdir
eCryptfs wasn't clearing the eCryptfs inode's i_nlink after a successful
vfs_rmdir() on the lower directory. This resulted in the inode evict and
destroy paths to be missed.

https://bugs.launchpad.net/ecryptfs/+bug/723518

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
2011-05-27 11:46:14 -05:00
Sage Weil e4eaac06bc vfs: push dentry_unhash on rename_dir into file systems
Only a few file systems need this.  Start by pushing it down into each
rename method (except gfs2 and xfs) so that it can be dealt with on a
per-fs basis.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-26 07:26:48 -04:00
Sage Weil 79bf7c732b vfs: push dentry_unhash on rmdir into file systems
Only a few file systems need this.  Start by pushing it down into each
fs rmdir method (except gfs2 and xfs) so it can be dealt with on a per-fs
basis.

This does not change behavior for any in-tree file systems.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-26 07:26:47 -04:00
Tyler Hicks 5be79de2e1 eCryptfs: Flush dirty pages in setattr
After 57db4e8d73 changed eCryptfs to
write-back caching, eCryptfs page writeback updates the lower inode
times due to the use of vfs_write() on the lower file.

To preserve inode metadata changes, such as 'cp -p' does with
utimensat(), we need to flush all dirty pages early in
ecryptfs_setattr() so that the user-updated lower inode metadata isn't
clobbered later in writeback.

https://bugzilla.kernel.org/show_bug.cgi?id=33372

Reported-by: Rocko <rockorequin@hotmail.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-04-25 18:49:46 -05:00
Tyler Hicks 3aeb86ea4c eCryptfs: Handle failed metadata read in lookup
When failing to read the lower file's crypto metadata during a lookup,
eCryptfs must continue on without throwing an error. For example, there
may be a plaintext file in the lower mount point that the user wants to
delete through the eCryptfs mount.

If an error is encountered while reading the metadata in lookup(), the
eCryptfs inode's size could be incorrect. We must be sure to reread the
plaintext inode size from the metadata when performing an open() or
setattr(). The metadata is already being read in those paths, so this
adds minimal performance overhead.

This patch introduces a flag which will track whether or not the
plaintext inode size has been read so that an incorrect i_size can be
fixed in the open() or setattr() paths.

https://bugs.launchpad.net/bugs/509180

Cc: <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-04-25 18:45:06 -05:00
Tyler Hicks 332ab16f83 eCryptfs: Add reference counting to lower files
For any given lower inode, eCryptfs keeps only one lower file open and
multiplexes all eCryptfs file operations through that lower file. The
lower file was considered "persistent" and stayed open from the first
lookup through the lifetime of the inode.

This patch keeps the notion of a single, per-inode lower file, but adds
reference counting around the lower file so that it is closed when not
currently in use. If the reference count is at 0 when an operation (such
as open, create, etc.) needs to use the lower file, a new lower file is
opened. Since the file is no longer persistent, all references to the
term persistent file are changed to lower file.

Locking is added around the sections of code that opens the lower file
and assign the pointer in the inode info, as well as the code the fputs
the lower file when all eCryptfs users are done with it.

This patch is needed to fix issues, when mounted on top of the NFSv3
client, where the lower file is left silly renamed until the eCryptfs
inode is destroyed.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-04-25 18:32:37 -05:00
Tyler Hicks dd55c89852 eCryptfs: dput dentries returned from dget_parent
Call dput on the dentries previously returned by dget_parent() in
ecryptfs_rename(). This is needed for supported eCryptfs mounts on top
of the NFSv3 client.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-04-25 18:32:36 -05:00
Tyler Hicks 35ffa948b2 eCryptfs: Remove extra d_delete in ecryptfs_rmdir
vfs_rmdir() already calls d_delete() on the lower dentry. That was being
duplicated in ecryptfs_rmdir() and caused a NULL pointer dereference
when NFSv3 was the lower filesystem.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-04-25 18:32:35 -05:00
Lucas De Marchi 25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Roberto Sassu b5695d0463 eCryptfs: write lock requested keys
A requested key is write locked in order to prevent modifications on the
authentication token while it is being used.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:49:43 -05:00
Roberto Sassu 950983fc04 eCryptfs: move ecryptfs_find_auth_tok_for_sig() call before mutex_lock
The ecryptfs_find_auth_tok_for_sig() call is moved before the
mutex_lock(s->tfm_mutex) instruction in order to avoid possible deadlocks
that may occur by holding the lock on the two semaphores 'key->sem' and
's->tfm_mutex' in reverse order.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:49:42 -05:00
Roberto Sassu 0e1fc5ef47 eCryptfs: verify authentication tokens before their use
Authentication tokens content may change if another requestor calls the
update() method of the corresponding key. The new function
ecryptfs_verify_auth_tok_from_key() retrieves the authentication token from
the provided key and verifies if it is still valid before being used to
encrypt or decrypt an eCryptfs file.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
[tyhicks: Minor formatting changes]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:49:41 -05:00
Roberto Sassu 7762e230fd eCryptfs: modified size of keysig in the ecryptfs_key_sig structure
The size of the 'keysig' array is incremented of one byte in order to make
room for the NULL character. The 'keysig' variable is used, in the function
ecryptfs_generate_key_packet_set(), to find an authentication token with
the given signature and is printed a debug message if it cannot be
retrieved.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:49:40 -05:00
Roberto Sassu cf35ca6913 eCryptfs: removed num_global_auth_toks from ecryptfs_mount_crypt_stat
This patch removes the 'num_global_auth_toks' field of the
ecryptfs_mount_crypt_stat structure, used to count the number of items in
the 'global_auth_tok_list' list. This variable is not needed because there
are no checks based upon it.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:49:39 -05:00
Roberto Sassu 1821df040a eCryptfs: ecryptfs_keyring_auth_tok_for_sig() bug fix
The pointer '(*auth_tok_key)' is set to NULL in case request_key()
fails, in order to prevent its use by functions calling
ecryptfs_keyring_auth_tok_for_sig().

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Cc: <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:49:15 -05:00
Tyler Hicks 50f198ae16 eCryptfs: Unlock page in write_begin error path
Unlock the page in error path of ecryptfs_write_begin(). This may
happen, for example, if decryption fails while bring the page
up-to-date.

Cc: <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:47:46 -05:00
Thieu Le 57db4e8d73 ecryptfs: modify write path to encrypt page in writepage
Change the write path to encrypt the data only when the page is written to
disk in ecryptfs_writepage. Previously, ecryptfs encrypts the page in
ecryptfs_write_end which means that if there are multiple write requests to
the same page, ecryptfs ends up re-encrypting that page over and over again.
This patch minimizes the number of encryptions needed.

Signed-off-by: Thieu Le <thieule@chromium.org>
[tyhicks: Changed NULL .drop_inode sop pointer to generic_drop_inode]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:47:45 -05:00
Tyler Hicks fed8859b3a eCryptfs: Remove ECRYPTFS_NEW_FILE crypt stat flag
Now that grow_file() is not called in the ecryptfs_create() path, the
ECRYPTFS_NEW_FILE flag is no longer needed. It helped
ecryptfs_readpage() know not to decrypt zeroes that were read from the
lower file in the grow_file() path.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:47:44 -05:00
Tyler Hicks bd4f0fe8bb eCryptfs: Remove unnecessary grow_file() function
When creating a new eCryptfs file, the crypto metadata is written out
and then the lower file was being "grown" with 4 kB of encrypted zeroes.
I suspect that growing the encrypted file was to prevent an information
leak that the unencrypted file was empty. However, the unencrypted file
size is stored, in plaintext, in the metadata so growing the file is
unnecessary.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-03-28 01:47:43 -05:00
Tyler Hicks 55f9cf6bba eCryptfs: Copy up lower inode attrs in getattr
The lower filesystem may do some type of inode revalidation during a
getattr call. eCryptfs should take advantage of that by copying the
lower inode attributes to the eCryptfs inode after a call to
vfs_getattr() on the lower inode.

I originally wrote this fix while working on eCryptfs on nfsv3 support,
but discovered it also fixed an eCryptfs on ext4 nanosecond timestamp
bug that was reported.

https://bugs.launchpad.net/bugs/613873

Cc: <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-02-21 14:46:36 -06:00
Andy Whitcroft 323ef68faf ecryptfs: read on a directory should return EISDIR if not supported
read() calls against a file descriptor connected to a directory are
incorrectly returning EINVAL rather than EISDIR:

  [EISDIR]
    [XSI] [Option Start] The fildes argument refers to a directory and the
    implementation does not allow the directory to be read using read()
    or pread(). The readdir() function should be used instead. [Option End]

This occurs because we do not have a .read operation defined for
ecryptfs directories.  Connect this up to generic_read_dir().

BugLink: http://bugs.launchpad.net/bugs/719691
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-02-21 14:46:36 -06:00
Tyler Hicks 70b8902199 eCryptfs: Handle NULL nameidata pointers
Allow for NULL nameidata pointers in eCryptfs create, lookup, and
d_revalidate functions.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-02-21 14:45:57 -06:00
Tyler Hicks 8787c7a3e0 eCryptfs: Revert "dont call lookup_one_len to avoid NULL nameidata"
This reverts commit 21edad3220 and commit
93c3fe40c2, which fixed a regression by
the former.

Al Viro pointed out bypassed dcache lookups in
ecryptfs_new_lower_dentry(), misuse of vfs_path_lookup() in
ecryptfs_lookup_one_lower() and a dislike of passing nameidata to the
lower filesystem.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-02-17 20:30:29 -06:00
Frank Swiderski 24562486be ecryptfs: remove unnecessary decrypt when extending a file
Removes an unecessary page decrypt from ecryptfs_begin_write when the
page is beyond the current file size. Previously, the call to
ecryptfs_decrypt_page would result in a read of 0 bytes, but still
attempt to decrypt an entire page. This patch detects that case and
merely zeros the page before marking it up-to-date.

Signed-off-by: Frank Swiderski <fes@chromium.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 13:01:25 -06:00
Tyler Hicks f24b38874e ecryptfs: Fix ecryptfs_printk() size_t warnings
Commit cb55d21f6fa19d8c6c2680d90317ce88c1f57269 revealed a number of
missing 'z' length modifiers in calls to ecryptfs_printk() when
printing variables of type size_t. This patch fixes those compiler
warnings.

Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 13:01:24 -06:00
Joe Perches 888d57bbc9 fs/ecryptfs: Add printf format/argument verification and fix fallout
Add __attribute__((format... to __ecryptfs_printk
Make formats and arguments match.
Add casts to (unsigned long long) for %llu.

Signed-off-by: Joe Perches <joe@perches.com>
[tyhicks: 80 columns cleanup and fixed typo]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 13:01:23 -06:00
Roberto Sassu 0abe116947 ecryptfs: fixed testing of file descriptor flags
This patch replaces the check (lower_file->f_flags & O_RDONLY) with
((lower_file & O_ACCMODE) == O_RDONLY).

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 11:24:43 -06:00
Roberto Sassu 27992890b0 ecryptfs: test lower_file pointer when lower_file_mutex is locked
This patch prevents the lower_file pointer in the 'ecryptfs_inode_info'
structure to be checked when the mutex 'lower_file_mutex' is not locked.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 11:24:42 -06:00
Roberto Sassu 070baa5128 ecryptfs: missing initialization of the superblock 'magic' field
This patch initializes the 'magic' field of ecryptfs filesystems to
ECRYPTFS_SUPER_MAGIC.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
[tyhicks: merge with 66cb76666d]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 11:23:01 -06:00
Roberto Sassu 2a8652f4e0 ecryptfs: moved ECRYPTFS_SUPER_MAGIC definition to linux/magic.h
The definition of ECRYPTFS_SUPER_MAGIC has been moved to the include
file 'linux/magic.h' to become available to other kernel subsystems.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 10:44:31 -06:00
Edward Shishkin 38a708d775 ecryptfs: fix truncation error in ecryptfs_read_update_atime
This is similar to the bug found in direct-io not so long ago.

Fix up truncation (ssize_t->int).  This only matters with >2G
reads/writes, which the kernel doesn't permit.

Signed-off-by: Edward Shishkin <edward.shishkin@gmail.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Eric Sandeen <esandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
2011-01-17 10:44:30 -06:00
Linus Torvalds 6254b32b57 ecryptfs: fix broken build
Stephen Rothwell reports that the vfs merge broke the build of ecryptfs.
The breakage comes from commit 66cb76666d ("sanitize ecryptfs
->mount()") which was obviously not even build tested. Tssk, tssk, Al.

This is the minimal build fixup for the situation, although I don't have
a filesystem to actually test it with.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 17:19:38 -08:00
Al Viro 66cb76666d sanitize ecryptfs ->mount()
kill ecryptfs_read_super(), reorder code allowing to use
normal d_alloc_root() instead of opencoding it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-01-12 20:04:37 -05:00
Nick Piggin b74c79e993 fs: provide rcu-walk aware permission i_ops
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:29 +11:00
Nick Piggin 34286d6662 fs: rcu-walk aware d_revalidate method
Require filesystems be aware of .d_revalidate being called in rcu-walk
mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning
-ECHILD from all implementations.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:29 +11:00
Nick Piggin fb045adb99 fs: dcache reduce branches in lookup path
Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.

Patched with:

git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:28 +11:00
Nick Piggin fa0d7e3de6 fs: icache RCU free inodes
RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page->mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:26 +11:00
Nick Piggin b7ab39f631 fs: dcache scale dentry refcount
Make d_count non-atomic and protect it with d_lock. This allows us to ensure a
0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when
we start protecting many other dentry members with d_lock.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:21 +11:00
Nick Piggin b1e6a015a5 fs: change d_hash for rcu-walk
Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.

For in-tree filesystems, this is just a mechanical change.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07 17:50:20 +11:00
Arnd Bergmann 451a3c24b0 BKL: remove extraneous #include <smp_lock.h>
The big kernel lock has been removed from all these files at some point,
leaving only the #include.

Remove this too as a cleanup.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-11-17 08:59:32 -08:00