- 11 Jul, 2014 7 commits
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Jeff Layton authored
The current enforcement of deny modes is both inefficient and scattered across several places, which makes it hard to guarantee atomicity. The inefficiency is a problem now, and the lack of atomicity will mean races once the client_mutex is removed. First, we address the inefficiency. We have to track deny modes on a per-stateid basis to ensure that open downgrades are sane, but when the server goes to enforce them it has to walk the entire list of stateids and check against each one. Instead of doing that, maintain a per-nfs4_file deny mode. When a file is opened, we simply set any deny bits in that mode that were specified in the OPEN call. We can then use that unified deny mode to do a simple check to see whether there are any conflicts without needing to walk the entire stateid list. The only time we'll need to walk the entire list of stateids is when a stateid that has a deny mode on it is being released, or one is having its deny mode downgraded. In that case, we must walk the entire list and recalculate the fi_share_deny field. Since deny modes are pretty rare today, this should be very rare under normal workloads. To address the potential for races once the client_mutex is removed, protect fi_share_deny with the fi_lock. In nfs4_get_vfs_file, check to make sure that any deny mode we want to apply won't conflict with existing access. If that's ok, then have nfs4_file_get_access check that new access to the file won't conflict with existing deny modes. If that also passes, then get file access references, set the correct access and deny bits in the stateid, and update the fi_share_deny field. If opening the file or truncating it fails, then unwind the whole mess and return the appropriate error. Signed-off-by:
Jeff Layton <jlayton@primarydata.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
J. Bruce Fields <bfields@redhat.com>
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Jeff Layton authored
Once we remove the client_mutex, there's an unlikely but possible race that could occur. It will be possible for nfs4_file_put_access to race with nfs4_file_get_access. The refcount will go to zero (briefly) and then bumped back to one. If that happens we set ourselves up for a use-after-free and the potential for a lock to race onto the i_flock list as a filp is being torn down. Ensure that we can safely bump the refcount on the file by holding the fi_lock whenever that's done. The only place it currently isn't is in get_lock_access. In order to ensure atomicity with finding the file, use the find_*_file_locked variants and then call get_lock_access to get new access references on the nfs4_file under the same lock. Signed-off-by:
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Jeff Layton authored
Fix the "deny" argument type, and start the loop at 1. The 0 iteration is always a noop. Signed-off-by:
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Jeff Layton authored
Cleanup -- ensure that the stateid bits are set at the same time that the file access refcounts are incremented. Keeping them coherent like this makes it easier to ensure that we account for all of the references. Since the initialization of the st_*_bmap fields is done when it's hashed, we go ahead and hash the stateid before getting access to the file and unhash it if that function returns error. This will be necessary anyway in a follow-on patch that will overhaul deny mode handling. Signed-off-by:
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Jeff Layton authored
We never use anything above bit #3, so an unsigned long for each is wasteful. Shrink them to a char each, and add some WARN_ON_ONCE calls if we try to set or clear bits that would go outside those sizes. Note too that because atomic bitops work on unsigned longs, we have to abandon their use here. That shouldn't be a problem though since we don't really care about the atomicity in this code anyway. Using them was just a convenient way to flip bits. Signed-off-by:
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Jeff Layton authored
...and replace it with a simple swap call. Signed-off-by:
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Jeff Layton authored
Have them take NFS4_SHARE_ACCESS_* flags instead of an open mode. This spares the callers from having to convert it themselves. This also allows us to simplify these functions as we no longer need to do the access_to_omode conversion in either one. Note too that this patch eliminates the WARN_ON in __nfs4_file_get_access. It's valid for now, but in a later patch we'll be bumping the refcounts prior to opening the file in order to close some races, at which point we'll need to remove it anyway. Signed-off-by:
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- 10 Jul, 2014 17 commits
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Trond Myklebust authored
Use filp_close instead of open coding. filp_close does a bit more than just release the locks and put the filp. It also calls ->flush and dnotify_flush, both of which should be done here anyway. Signed-off-by:
Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by:
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Trond Myklebust authored
Preparation for removal of the client_mutex, which currently protects this array. While we don't actually need the find_*_file_locked variants just yet, a later patch will. So go ahead and add them now to reduce future churn in this code. Signed-off-by:
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Trond Myklebust authored
Access to this list is currently serialized by the client_mutex. Add finer grained locking around this list in preparation for its removal. Signed-off-by:
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Jeff Layton authored
No need to take the lock unless the count goes to 0. Signed-off-by:
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Jeff Layton authored
Bruce says: There's also a preexisting expire_client/laundromat vs break race: - expire_client/laundromat adds a delegation to its local reaplist using the same dl_recall_lru field that a delegation uses to track its position on the recall lru and drops the state lock. - a concurrent break_lease adds the delegation to the lru. - expire/client/laundromat then walks it reaplist and sees the lru head as just another delegation on the list.... Fix this race by checking the dl_time under the state_lock. If we find that it's not 0, then we know that it has already been queued to the LRU list and that we shouldn't queue it again. In the case of destroy_client, we must also ensure that we don't hit similar races by ensuring that we don't move any delegations to the reaplist with a dl_time of 0. Just bump the dl_time by one before we drop the state_lock. We're destroying the delegations anyway, so a 1s difference there won't matter. The fault injection code also requires a bit of surgery here: First, in the case of nfsd_forget_client_delegations, we must prevent the same sort of race vs. the delegation break callback. For that, we just increment the dl_time to ensure that a delegation callback can't race in while we're working on it. We can't do that for nfsd_recall_client_delegations, as we need to have it actually queue the delegation, and that won't happen if we increment the dl_time. The state lock is held over that function, so we don't need to worry about these sorts of races there. There is one other potential bug nfsd_recall_client_delegations though. Entries on the victims list are not dequeued before calling nfsd_break_one_deleg. That's a potential list corruptor, so ensure that we do that there. Reported-by:"J. Bruce Fields" <bfields@fieldses.org> Signed-off-by:
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Kinglong Mee authored
Commit 8c7424cf (nfsd4: don't try to encode conflicting owner if low on space) forgot free conf->data in nfsd4_encode_lockt and before sign conf->data to NULL in nfsd4_encode_lock_denied. Signed-off-by:
Kinglong Mee <kinglongmee@gmail.com> Signed-off-by:
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Trond Myklebust authored
lookup_clientid is preferable to find_confirmed_client since it's able to use the cached client in the compound state. Signed-off-by:
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Trond Myklebust authored
In later patches, we'll be moving the stateowner table into the nfs4_client, and by doing this we ensure that we have a cached nfs4_client pointer. Signed-off-by:
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Trond Myklebust authored
...and have alloc_init_open_stateowner just use the cstate->clp pointer instead of passing in a clp separately. This allows us to use the cached nfs4_client pointer in the cstate instead of having to look it up again. Signed-off-by:
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Jeff Layton authored
We want to use the nfsd4_compound_state to cache the nfs4_client in order to optimise away extra lookups of the clid. In the v4.0 case, we use this to ensure that we only have to look up the client at most once per compound for each call into lookup_clientid. For v4.1+ we set the pointer in the cstate during SEQUENCE processing so we should never need to do a search for it. Signed-off-by:
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Jeff Layton authored
I saw this pop up with some pynfs testing: [ 123.609992] nfsd: non-standard errno: -7 ...and -7 is -E2BIG. I think what happened is that XFS returned -E2BIG due to some xattr operations with the ACL10 pynfs TEST (I guess it has limited xattr size?). Add a better mapping for that error since it's possible that we'll need it. How about we convert it to NFSERR_FBIG? As Bruce points out, they both have "BIG" in the name so it must be good. Also, turn the printk in this function into a WARN() so that we can get a bit more information about situations that don't have proper mappings. Signed-off-by: -
Jeff Layton authored
Commit 2a7420c03e504 (nfsd: Ensure that nfsd_create_setattr commits files to stable storage), added a couple of calls to commit_metadata, but doesn't convert their return codes to __be32 in the appropriate places. Cc: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by:
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Trond Myklebust authored
The cstate already holds information about the session, and hence the client id, so it makes more sense to pass that information rather than the current practice of passing a 'minor version' number. Signed-off-by:
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Trond Myklebust authored
If the client were to disappear from underneath us while we're holding a session reference, things would be bad. This cleanup helps ensure that it cannot, which will be a possibility when the client_mutex is removed. Signed-off-by:
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Jeff Layton authored
Now that we know that we won't have several lockowners with the same, owner->data, we can simplify nfsd4_release_lockowner and get rid of the lo_list in the process. Signed-off-by:
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Trond Myklebust authored
Just like open-owners, lock-owners are associated with a name, a clientid and, in the case of minor version 0, a sequence id. There is no association to a file. Signed-off-by:
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Jeff Layton authored
A lockowner can have more than one lock stateid. For instance, if a process has more than one file open and has locks on both, then the same lockowner has more than one stateid associated with it. Change it so that this reality is better reflected by the objects that nfsd uses. Signed-off-by:
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- 08 Jul, 2014 16 commits
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Trond Myklebust authored
In the NFSv4 spec, lock stateids are per-file objects. Lockowners are not. This patch replaces the current list of lock owners in the open stateids with a list of lock stateids. Signed-off-by:
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Trond Myklebust authored
Minor cleanup that should introduce no behavioral changes. Currently this function just unhashes the stateid and leaves the caller to do the work of the CLOSE processing. Change nfsd4_close_open_stateid so that it handles doing all of the work of closing a stateid. Move the handling of the unhashed stateid into it instead of doing that work in nfsd4_close. This will help isolate some coming changes to stateid handling from nfsd4_close. Signed-off-by:
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Jeff Layton authored
There's no need to confirm an openowner in v4.1 and above, so we can go ahead and set NFS4_OO_CONFIRMED when we create openowners in those versions. This will also be necessary when we remove the client_mutex, as it'll be possible for two concurrent opens to race in versions >4.0. Signed-off-by:
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Trond Myklebust authored
Move the slot return, put session etc into a helper in fs/nfsd/nfs4state.c instead of open coding in nfs4svc_encode_compoundres. Signed-off-by:
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Trond Myklebust authored
Not technically a bugfix, since nothing tries to use the return pointer if this function doesn't return success, but it could be a problem with some coming changes. Signed-off-by:
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Jeff Layton authored
Currently, the maximum number of connections that nfsd will allow is based on the number of threads spawned. While this is fine for a default, there really isn't a clear relationship between the two. The number of threads corresponds to the number of concurrent requests that we want to allow the server to process at any given time. The connection limit corresponds to the maximum number of clients that we want to allow the server to handle. These are two entirely different quantities. Break the dependency on increasing threads in order to allow for more connections, by adding a new per-net parameter that can be set to a non-zero value. The default is still to base it on the number of threads, so there should be no behavior change for anyone who doesn't use it. Cc: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by:
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Trond Myklebust authored
Since nfsd_create_setattr strips the mode from the struct iattr, it is quite possible that it will optimise away the call to nfsd_setattr altogether. If this is the case, then we never call commit_metadata() on the newly created file. Also ensure that both nfsd_setattr() and nfsd_create_setattr() fail when the call to commit_metadata fails. Signed-off-by:
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Kinglong Mee authored
Commit db2e747b (vfs: remove mode parameter from vfs_symlink()) have remove mode parameter from vfs_symlink. So that, iattr isn't needed by nfsd_symlink now, just remove it. Signed-off-by:
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Trond Myklebust authored
Current code depends on the client_mutex to guarantee a single struct nfs4_file per inode in the file_hashtbl and make addition atomic with respect to lookup. Rely instead on the state_Lock, to make it easier to stop taking the client_mutex here later. To prevent an i_lock/state_lock inversion, change nfsd4_init_file to use ihold instead if igrab. That's also more efficient anyway as we definitely hold a reference to the inode at that point. Signed-off-by:
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Christoph Hellwig authored
nfsd4_process_open2 will currently will get access to the file, and then call nfsd4_truncate to (possibly) truncate it. If that operation fails though, then the access references will never be released as the nfs4_ol_stateid is never initialized. Fix by moving the nfsd4_truncate call into nfs4_get_vfs_file, ensuring that the refcounts are properly put if the truncate fails. Signed-off-by:
Christoph Hellwig <hch@infradead.org> Signed-off-by:
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Kinglong Mee authored
fs/nfsd/nfs4xdr.c: In function 'nfsd4_encode_readv': >> fs/nfsd/nfs4xdr.c:3137:148: warning: comparison of distinct pointer types lacks a cast [enabled by default] thislen = min(len, ((void *)xdr->end - (void *)xdr->p)); Reported-by:
Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:
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J. Bruce Fields authored
Avoid an extra allocation for the tmpbuf struct itself, and stop ignoring some allocation failures. Signed-off-by: -
J. Bruce Fields authored
This is a not-that-useful kmalloc wrapper. And I'd like one of the callers to actually use something other than kmalloc. Signed-off-by: -
J. Bruce Fields authored
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J. Bruce Fields authored
28e05dd8 "knfsd: nfsd4: represent nfsv4 acl with array instead of linked list" removed the last user that wanted a custom free function. Signed-off-by:
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J. Bruce Fields authored
The name of a link is currently stored in cr_name and cr_namelen, and the content in cr_linkname and cr_linklen. That's confusing. Signed-off-by:
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