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git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
ceph: fix get_ticket_handler() error handling
ceph: don't BUG on ENOMEM during mds reconnect
ceph: ceph_mdsc_build_path() returns an ERR_PTR
ceph: Fix warnings
ceph: ceph_get_inode() returns an ERR_PTR
ceph: initialize fields on new dentry_infos
ceph: maintain i_head_snapc when any caps are dirty, not just for data
ceph: fix osd request lru adjustment when sending request
ceph: don't improperly set dir complete when holding EXCL cap
mm: exporting account_page_dirty
ceph: direct requests in snapped namespace based on nonsnap parent
ceph: queue cap snap writeback for realm children on snap update
ceph: include dirty xattrs state in snapped caps
ceph: fix xattr cap writeback
ceph: fix multiple mds session shutdown
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* 'for-2.6.36' of git://linux-nfs.org/~bfields/linux:
nfsd: fix NULL dereference in nfsd_statfs()
nfsd4: fix downgrade/lock logic
nfsd4: typo fix in find_any_file
nfsd4: bad BUG() in preprocess_stateid_op
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The commit ebabe9a9001af0af56c0c2780ca1576246e7a74b
pass a struct path to vfs_statfs
introduced the struct path initialization, and this seems to trigger
an Oops on my machine.
fh_dentry field may be NULL and set later in fh_verify(), thus the
initialization of path must be after fh_verify().
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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If we already had a RW open for a file, and get a readonly open, we were
piggybacking on the existing RW open. That's inconsistent with the
downgrade logic which blows away the RW open assuming you'll still have
a readonly open.
Also, make sure there is a readonly or writeonly open available for
locking, again to prevent bad behavior in downgrade cases when any RW
open may be lost.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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It's OK for this function to return without setting filp--we do it in
the special-stateid case.
And there's a legitimate case where we can hit this, since we do permit
reads on write-only stateid's.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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On 08/26/2010 01:56 AM, joe hefner wrote:
> On a recent Fedora (13), I am seeing a mount failure message that I can not explain. I have a Windows Server 2003ýa with a share set up for access only for a specific username (say userfoo). If I try to mount it from Linux,ýusing userfoo and the correct password all is well. If I try with a bad password or with some other username (userbar), it fails with "Permission denied" as expected. If I try to mount as username = administrator, and give the correct administrator password, I would also expect "Permission denied", but I see "Cannot allocate memory" instead.
> ýfs/cifs/netmisc.c: Mapping smb error code 5 to POSIX err -13
> ýfs/cifs/cifssmb.c: Send error in QPathInfo = -13
> ýCIFS VFS: cifs_read_super: get root inode failed
Looks like the commit 0b8f18e3 assumed that cifs_get_inode_info() and
friends fail only due to memory allocation error when the inode is NULL
which is not the case if CIFSSMBQPathInfo() fails and returns an error.
Fix this by propagating the actual error code back.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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get_ticket_handler() returns a valid pointer or it returns
ERR_PTR(-ENOMEM) if kzalloc() fails.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
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We are in a position to return an error; do that instead.
Signed-off-by: Sage Weil <sage@newdream.net>
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ceph_mdsc_build_path() returns an ERR_PTR but this code is set up to
handle NULL returns.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
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CC: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Just scrubbing some warnings so I can see real problem ones in the build
noise. For 32bit we need to coax gcc politely into believing we really
honestly intend to the casts. Using (u64)(unsigned long) means we cast from
a pointer to a type of the right size and then extend it. This stops the
warning spew.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Sage Weil <sage@newdream.net>
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ceph_get_inode() returns an ERR_PTR and it doesn't return a NULL.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
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* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
Eliminate sparse warning - bad constant expression
cifs: check for NULL session password
missing changes during ntlmv2/ntlmssp auth and sign
[CIFS] Fix ntlmv2 auth with ntlmssp
cifs: correction of unicode header files
cifs: fix NULL pointer dereference in cifs_find_smb_ses
cifs: consolidate error handling in several functions
cifs: clean up error handling in cifs_mknod
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Signed-off-by: Sage Weil <sage@newdream.net>
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We used to use i_head_snapc to keep track of which snapc the current epoch
of dirty data was dirtied under. It is used by queue_cap_snap to set up
the cap_snap. However, since we queue cap snaps for any dirty caps, not
just for dirty file data, we need to keep a valid i_head_snapc anytime
we have dirty|flushing caps. This fixes a NULL pointer deref in
queue_cap_snap when writing back dirty caps without data (e.g.,
snaptest-authwb.sh).
Signed-off-by: Sage Weil <sage@newdream.net>
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Eliminiate sparse warning during usage of crypto_shash_* APIs
error: bad constant expression
Allocate memory for shash descriptors once, so that we do not kmalloc/kfree it
for every signature generation (shash descriptor for md5 hash).
From ed7538619817777decc44b5660b52268077b74f3 Mon Sep 17 00:00:00 2001
From: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Date: Tue, 24 Aug 2010 11:47:43 -0500
Subject: [PATCH] eliminate sparse warnings during crypto_shash_* APis usage
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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If xfs_map_blocks returns EAGAIN because of lock contention we must redirty the
page and not disard the pagecache content and return an error from writepage.
We used to do this correctly, but the logic got lost during the recent
reshuffle of the writepage code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Mike Gao <ygao.linux@gmail.com>
Tested-by: Mike Gao <ygao.linux@gmail.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
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Formatting items requires memory allocation when using delayed
logging. Currently that memory allocation is done while holding the
CIL context lock in read mode. This means that if memory allocation
takes some time (e.g. enters reclaim), we cannot push on the CIL
until the allocation(s) required by formatting complete. This can
stall CIL pushes for some time, and once a push is stalled so are
all new transaction commits.
Fix this splitting the item formatting into two steps. The first
step which does the allocation and memcpy() into the allocated
buffer is now done outside the CIL context lock, and only the CIL
insert is done inside the CIL context lock. This avoids the stall
issue.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Delayed logging adds some serialisation to the log force process to
ensure that it does not deference a bad commit context structure
when determining if a CIL push is necessary or not. It does this by
grabing the CIL context lock exclusively, then dropping it before
pushing the CIL if necessary. This causes serialisation of all log
forces and pushes regardless of whether a force is necessary or not.
As a result fsync heavy workloads (like dbench) can be significantly
slower with delayed logging than without.
To avoid this penalty, copy the current sequence from the context to
the CIL structure when they are swapped. This allows us to do
unlocked checks on the current sequence without having to worry
about dereferencing context structures that may have already been
freed. Hence we can remove the CIL context locking in the forcing
code and only call into the push code if the current context matches
the sequence we need to force.
By passing the sequence into the push code, we can check the
sequence again once we have the CIL lock held exclusive and abort if
the sequence has already been pushed. This avoids a lock round-trip
and unnecessary CIL pushes when we have racing push calls.
The result is that the regression in dbench performance goes away -
this change improves dbench performance on a ramdisk from ~2100MB/s
to ~2500MB/s. This compares favourably to not using delayed logging
which retuns ~2500MB/s for the same workload.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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When we need to cover the log, we issue dummy transactions to ensure
the current log tail is on disk. Unfortunately we currently use the
root inode in the dummy transaction, and the act of committing the
transaction dirties the inode at the VFS level.
As a result, the VFS writeback of the dirty inode will prevent the
filesystem from idling long enough for the log covering state
machine to complete. The state machine gets stuck in a loop issuing
new dummy transactions to cover the log and never makes progress.
To avoid this problem, the dummy transactions should not cause
externally visible state changes. To ensure this occurs, make sure
that dummy transactions log an unchanging field in the superblock as
it's state is never propagated outside the filesystem. This allows
the log covering state machine to complete successfully and the
filesystem now correctly enters a fully idle state about 90s after
the last modification was made.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Because of delayed updates to sb_icount field in the super block, it
is possible to allocate over maxicount number of inodes. This
causes the arithmetic to calculate a negative number of free inodes
in user commands like df or stat -f.
Since maxicount is a somewhat arbitrary number, a slight over
allocation is not critical but user commands should be displayed as
0 or greater and never go negative. To do this the value in the
stats buffer f_ffree is capped to never go negative.
[ Modified to use max_t as per Christoph's comment. ]
Signed-off-by: Stu Brodsky <sbrodsky@sgi.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
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During data integrity (WB_SYNC_ALL) writeback, wbc->nr_to_write will
go negative on inodes with more than 1024 dirty pages due to
implementation details of write_cache_pages(). Currently XFS will
abort page clustering in writeback once nr_to_write drops below
zero, and so for data integrity writeback we will do very
inefficient page at a time allocation and IO submission for inodes
with large numbers of dirty pages.
Fix this by only aborting the page clustering code when
wbc->nr_to_write is negative and the sync mode is WB_SYNC_NONE.
Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Commit 7124fe0a5b619d65b739477b3b55a20bf805b06d ("xfs: validate untrusted inode
numbers during lookup") changes the inode lookup code to do btree lookups for
untrusted inode numbers. This change made an invalid assumption about the
alignment of inodes and hence incorrectly calculated the first inode in the
cluster. As a result, some inode numbers were being incorrectly considered
invalid when they were actually valid.
The issue was not picked up by the xfstests suite because it always runs fsr
and dump (the two utilities that utilise the bulkstat interface) on cache hot
inodes and hence the lookup code in the cold cache path was not sufficiently
exercised to uncover this intermittent problem.
Fix the issue by relaxing the btree lookup criteria and then checking if the
record returned contains the inode number we are lookup for. If it we get an
incorrect record, then the inode number is invalid.
Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Under heavy load parallel metadata loads (e.g. dbench), we can fail
to mark all the inodes in a cluster being freed as XFS_ISTALE as we
skip inodes we cannot get the XFS_ILOCK_EXCL or the flush lock on.
When this happens and the inode cluster buffer has already been
marked stale and freed, inode reclaim can try to write the inode out
as it is dirty and not marked stale. This can result in writing th
metadata to an freed extent, or in the case it has already
been overwritten trigger a magic number check failure and return an
EUCLEAN error such as:
Filesystem "ram0": inode 0x442ba1 background reclaim flush failed with 117
Fix this by ensuring that we hoover up all in memory inodes in the
cluster and mark them XFS_ISTALE when freeing the cluster.
Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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When we commit a transaction using delayed logging, we need to
unlock the items in the transaciton before we unlock the CIL context
and allow it to be checkpointed. If we unlock them after we release
the CIl context lock, the CIL can checkpoint and complete before
we free the log items. This breaks stale buffer item unlock and
unpin processing as there is an implicit assumption that the unlock
will occur before the unpin.
Also, some log items need to store the LSN of the transaction commit
in the item (inodes and EFIs) and so can race with other transaction
completions if we don't prevent the CIL from checkpointing before
the unlock occurs.
Cc: <stable@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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It's possible for a cifsSesInfo struct to have a NULL password, so we
need to check for that prior to running strncmp on it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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Fix argument order. We want to move the item to the end of the list, not
change the position of the head.
Signed-off-by: Henry C Chang <henry_c_chang@tcloudcomputing.com>
Signed-off-by: Sage Weil <sage@newdream.net>
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If we hold the EXCL cap, we cannot trust the dir stats from the MDS (num
files, subdirs) and must not incorrectly conclude that the directory is
empty. If we do, we get can bad results from lookup (bad ENOENT) and
bad readdir results.
Signed-off-by: Sage Weil <sage@newdream.net>
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This allows code outside of the mm core to safely manipulate page state
and not worry about the other accounting. Not using these routines means
that some code will lose track of the accounting and we get bugs. This
has happened once already.
Signed-off-by: Michael Rubin <mrubin@google.com>
Signed-off-by: Sage Weil <sage@newdream.net>
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When making a request in the virtual snapdir or a snapped portion of the
namespace, we should choose the MDS based on the first nonsnap parent (and
its caps). If that is not the best place, we will get forward hints to
find the right MDS in the cluster. This fixes ESTALE errors when using
the .snap directory and namespace with multiple MDSs.
Signed-off-by: Sage Weil <sage@newdream.net>
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When a realm is updated, we need to queue writeback on inodes in that
realm _and_ its children. Otherwise, if the inode gets cowed on the
server, we can get a hang later due to out-of-sync cap/snap state.
Signed-off-by: Sage Weil <sage@newdream.net>
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When we snapshot dirty metadata that needs to be written back to the MDS,
include dirty xattr metadata. Make the capsnap reference the encoded
xattr blob so that it will be written back in the FLUSHSNAP op.
Also fix the capsnap creation guard to include dirty auth or file bits,
not just tests specific to dirty file data or file writes in progress
(this fixes auth metadata writeback).
Signed-off-by: Sage Weil <sage@newdream.net>
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We should include the xattr metadata blob in the cap update message any
time we are flushing dirty state, NOT just when we are also dropping the
cap. This fixes async xattr writeback.
Also, clean up the code slightly to avoid duplicating the bit test.
Signed-off-by: Sage Weil <sage@newdream.net>
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The use of a completion when waiting for session shutdown during umount is
inappropriate, given the complexity of the condition. For multiple MDS's,
this resulted in the umount thread spinning, often preventing the session
close message from being processed in some cases.
Switch to a waitqueue and defined a condition helper. This cleans things
up nicely.
Signed-off-by: Sage Weil <sage@newdream.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
nilfs2: wait for discard to finish
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Make ntlmv2 as an authentication mechanism within ntlmssp
instead of ntlmv1.
Parse type 2 response in ntlmssp negotiation to pluck
AV pairs and use them to calculate ntlmv2 response token.
Also, assign domain name from the sever response in type 2
packet of ntlmssp and use that (netbios) domain name in
calculation of response.
Enable cifs/smb signing using rc4 and md5.
Changed name of the structure mac_key to session_key to reflect
the type of key it holds.
Use kernel crypto_shash_* APIs instead of the equivalent cifs functions.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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This patch corrects a problem of compilation errors at removal of
UNIUPR_NOLOWER definition and adds include guards to cifs_unicode.h.
Signed-off-by: Igor Druzhinin <jaxbrigs@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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* 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6:
NFS: Fix an Oops in the NFSv4 atomic open code
NFS: Fix the selection of security flavours in Kconfig
NFS: fix the return value of nfs_file_fsync()
rpcrdma: Fix SQ size calculation when memreg is FRMR
xprtrdma: Do not truncate iova_start values in frmr registrations.
nfs: Remove redundant NULL check upon kfree()
nfs: Add "lookupcache" to displayed mount options
NFS: allow close-to-open cache semantics to apply to root of NFS filesystem
SUNRPC: fix NFS client over TCP hangs due to packet loss (Bug 16494)
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cifs_find_smb_ses assumes that the vol->password field is a valid
pointer, but that's only the case if a password was passed in via
the options string. It's possible that one won't be if there is
no mount helper on the box.
Reported-by: diabel <gacek-2004@wp.pl>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
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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:
fs: brlock vfsmount_lock
fs: scale files_lock
lglock: introduce special lglock and brlock spin locks
tty: fix fu_list abuse
fs: cleanup files_lock locking
fs: remove extra lookup in __lookup_hash
fs: fs_struct rwlock to spinlock
apparmor: use task path helpers
fs: dentry allocation consolidation
fs: fix do_lookup false negative
mbcache: Limit the maximum number of cache entries
hostfs ->follow_link() braino
hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy
remove SWRITE* I/O types
kill BH_Ordered flag
vfs: update ctime when changing the file's permission by setfacl
cramfs: only unlock new inodes
fix reiserfs_evict_inode end_writeback second call
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nilfs_discard_segment() doesn't wait for completion of discard
requests. This specifies BLKDEV_IFL_WAIT flag when calling
blkdev_issue_discard() in order to fix the sync failure.
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@lst.de>
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Adam Lackorzynski reports:
with 2.6.35.2 I'm getting this reproducible Oops:
[ 110.825396] BUG: unable to handle kernel NULL pointer dereference at
(null)
[ 110.828638] IP: [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4
[ 110.828638] PGD be89f067 PUD bf18f067 PMD 0
[ 110.828638] Oops: 0000 [#1] SMP
[ 110.828638] last sysfs file: /sys/class/net/lo/operstate
[ 110.828638] CPU 2
[ 110.828638] Modules linked in: rtc_cmos rtc_core rtc_lib amd64_edac_mod
i2c_amd756 edac_core i2c_core dm_mirror dm_region_hash dm_log dm_snapshot
sg sr_mod usb_storage ohci_hcd mptspi tg3 mptscsih mptbase usbcore nls_base
[last unloaded: scsi_wait_scan]
[ 110.828638]
[ 110.828638] Pid: 11264, comm: setchecksum Not tainted 2.6.35.2 #1
[ 110.828638] RIP: 0010:[<ffffffff811247b7>] [<ffffffff811247b7>]
encode_attrs+0x1a/0x2a4
[ 110.828638] RSP: 0000:ffff88003bf5b878 EFLAGS: 00010296
[ 110.828638] RAX: ffff8800bddb48a8 RBX: ffff88003bf5bb18 RCX:
0000000000000000
[ 110.828638] RDX: ffff8800be258800 RSI: 0000000000000000 RDI:
ffff88003bf5b9f8
[ 110.828638] RBP: 0000000000000000 R08: ffff8800bddb48a8 R09:
0000000000000004
[ 110.828638] R10: 0000000000000003 R11: ffff8800be779000 R12:
ffff8800be258800
[ 110.828638] R13: ffff88003bf5b9f8 R14: ffff88003bf5bb20 R15:
ffff8800be258800
[ 110.828638] FS: 0000000000000000(0000) GS:ffff880041e00000(0063)
knlGS:00000000556bd6b0
[ 110.828638] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b
[ 110.828638] CR2: 0000000000000000 CR3: 00000000be8ef000 CR4:
00000000000006e0
[ 110.828638] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[ 110.828638] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
0000000000000400
[ 110.828638] Process setchecksum (pid: 11264, threadinfo
ffff88003bf5a000, task ffff88003f232210)
[ 110.828638] Stack:
[ 110.828638] 0000000000000000 ffff8800bfbcf920 0000000000000000
0000000000000ffe
[ 110.828638] <0> 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[ 110.828638] <0> 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[ 110.828638] Call Trace:
[ 110.828638] [<ffffffff81124c1f>] ? nfs4_xdr_enc_setattr+0x90/0xb4
[ 110.828638] [<ffffffff81371161>] ? call_transmit+0x1c3/0x24a
[ 110.828638] [<ffffffff813774d9>] ? __rpc_execute+0x78/0x22a
[ 110.828638] [<ffffffff81371a91>] ? rpc_run_task+0x21/0x2b
[ 110.828638] [<ffffffff81371b7e>] ? rpc_call_sync+0x3d/0x5d
[ 110.828638] [<ffffffff8111e284>] ? _nfs4_do_setattr+0x11b/0x147
[ 110.828638] [<ffffffff81109466>] ? nfs_init_locked+0x0/0x32
[ 110.828638] [<ffffffff810ac521>] ? ifind+0x4e/0x90
[ 110.828638] [<ffffffff8111e2fb>] ? nfs4_do_setattr+0x4b/0x6e
[ 110.828638] [<ffffffff8111e634>] ? nfs4_do_open+0x291/0x3a6
[ 110.828638] [<ffffffff8111ed81>] ? nfs4_open_revalidate+0x63/0x14a
[ 110.828638] [<ffffffff811056c4>] ? nfs_open_revalidate+0xd7/0x161
[ 110.828638] [<ffffffff810a2de4>] ? do_lookup+0x1a4/0x201
[ 110.828638] [<ffffffff810a4733>] ? link_path_walk+0x6a/0x9d5
[ 110.828638] [<ffffffff810a42b6>] ? do_last+0x17b/0x58e
[ 110.828638] [<ffffffff810a5fbe>] ? do_filp_open+0x1bd/0x56e
[ 110.828638] [<ffffffff811cd5e0>] ? _atomic_dec_and_lock+0x30/0x48
[ 110.828638] [<ffffffff810a9b1b>] ? dput+0x37/0x152
[ 110.828638] [<ffffffff810ae063>] ? alloc_fd+0x69/0x10a
[ 110.828638] [<ffffffff81099f39>] ? do_sys_open+0x56/0x100
[ 110.828638] [<ffffffff81027a22>] ? ia32_sysret+0x0/0x5
[ 110.828638] Code: 83 f1 01 e8 f5 ca ff ff 48 83 c4 50 5b 5d 41 5c c3 41
57 41 56 41 55 49 89 fd 41 54 49 89 d4 55 48 89 f5 53 48 81 ec 18 01 00 00
<8b> 06 89 c2 83 e2 08 83 fa 01 19 db 83 e3 f8 83 c3 18 a8 01 8d
[ 110.828638] RIP [<ffffffff811247b7>] encode_attrs+0x1a/0x2a4
[ 110.828638] RSP <ffff88003bf5b878>
[ 110.828638] CR2: 0000000000000000
[ 112.840396] ---[ end trace 95282e83fd77358f ]---
We need to ensure that the O_EXCL flag is turned off if the user doesn't
set O_CREAT.
Cc: stable@kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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fs: brlock vfsmount_lock
Use a brlock for the vfsmount lock. It must be taken for write whenever
modifying the mount hash or associated fields, and may be taken for read when
performing mount hash lookups.
A new lock is added for the mnt-id allocator, so it doesn't need to take
the heavy vfsmount write-lock.
The number of atomics should remain the same for fastpath rlock cases, though
code would be slightly slower due to per-cpu access. Scalability is not not be
much improved in common cases yet, due to other locks (ie. dcache_lock) getting
in the way. However path lookups crossing mountpoints should be one case where
scalability is improved (currently requiring the global lock).
The slowpath is slower due to use of brlock. On a 64 core, 64 socket, 32 node
Altix system (high latency to remote nodes), a simple umount microbenchmark
(mount --bind mnt mnt2 ; umount mnt2 loop 1000 times), before this patch it
took 6.8s, afterwards took 7.1s, about 5% slower.
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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fs: scale files_lock
Improve scalability of files_lock by adding per-cpu, per-sb files lists,
protected with an lglock. The lglock provides fast access to the per-cpu lists
to add and remove files. It also provides a snapshot of all the per-cpu lists
(although this is very slow).
One difficulty with this approach is that a file can be removed from the list
by another CPU. We must track which per-cpu list the file is on with a new
variale in the file struct (packed into a hole on 64-bit archs). Scalability
could suffer if files are frequently removed from different cpu's list.
However loads with frequent removal of files imply short interval between
adding and removing the files, and the scheduler attempts to avoid moving
processes too far away. Also, even in the case of cross-CPU removal, the
hardware has much more opportunity to parallelise cacheline transfers with N
cachelines than with 1.
A worst-case test of 1 CPU allocating files subsequently being freed by N CPUs
degenerates to contending on a single lock, which is no worse than before. When
more than one CPU are allocating files, even if they are always freed by
different CPUs, there will be more parallelism than the single-lock case.
Testing results:
On a 2 socket, 8 core opteron, I measure the number of times the lock is taken
to remove the file, the number of times it is removed by the same CPU that
added it, and the number of times it is removed by the same node that added it.
Booting: locks= 25049 cpu-hits= 23174 (92.5%) node-hits= 23945 (95.6%)
kbuild -j16 locks=2281913 cpu-hits=2208126 (96.8%) node-hits=2252674 (98.7%)
dbench 64 locks=4306582 cpu-hits=4287247 (99.6%) node-hits=4299527 (99.8%)
So a file is removed from the same CPU it was added by over 90% of the time.
It remains within the same node 95% of the time.
Tim Chen ran some numbers for a 64 thread Nehalem system performing a compile.
throughput
2.6.34-rc2 24.5
+patch 24.9
us sys idle IO wait (in %)
2.6.34-rc2 51.25 28.25 17.25 3.25
+patch 53.75 18.5 19 8.75
So significantly less CPU time spent in kernel code, higher idle time and
slightly higher throughput.
Single threaded performance difference was within the noise of microbenchmarks.
That is not to say penalty does not exist, the code is larger and more memory
accesses required so it will be slightly slower.
Cc: linux-kernel@vger.kernel.org
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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tty: fix fu_list abuse
tty code abuses fu_list, which causes a bug in remount,ro handling.
If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".
Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.
The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.
[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]
Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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fs: cleanup files_lock locking
Lock tty_files with a new spinlock, tty_files_lock; provide helpers to
manipulate the per-sb files list; unexport the files_lock spinlock.
Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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fs: remove extra lookup in __lookup_hash
Optimize lookup for create operations, where no dentry should often be
common-case. In cases where it is not, such as unlink, the added overhead
is much smaller than the removed.
Also, move comments about __d_lookup racyness to the __d_lookup call site.
d_lookup is intuitive; __d_lookup is what needs commenting. So in that same
vein, add kerneldoc comments to __d_lookup and clean up some of the comments:
- We are interested in how the RCU lookup works here, particularly with
renames. Make that explicit, and point to the document where it is explained
in more detail.
- RCU is pretty standard now, and macros make implementations pretty mindless.
If we want to know about RCU barrier details, we look in RCU code.
- Delete some boring legacy comments because we don't care much about how the
code used to work, more about the interesting parts of how it works now. So
comments about lazy LRU may be interesting, but would better be done in the
LRU or refcount management code.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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