summaryrefslogtreecommitdiff
path: root/fs/nfsd
AgeCommit message (Collapse)Author
2014-07-16nfsd: nfs4_alloc_init_lease should take a nfs4_file argJeff Layton
No need to pass the delegation pointer in here as it's only used to get the nfs4_file pointer. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-16nfsd: Avoid taking state_lock while holding inode lock in nfsd_break_one_delegJeff Layton
state_lock is a heavily contended global lock. We don't want to grab that while simultaneously holding the inode->i_lock. Add a new per-nfs4_file lock that we can use to protect the per-nfs4_file delegation list. Hold that while walking the list in the break_deleg callback and queue the workqueue job for each one. The workqueue job can then take the state_lock and do the list manipulations without the i_lock being held prior to starting the rpc call. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-16nfsd: eliminate nfsd4_init_callbackJeff Layton
It's just an obfuscated INIT_WORK call. Just make the work_func_t a non-static symbol and use a normal INIT_WORK call. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11NFSD: Fix bad checking of space for padding in splice readKinglong Mee
Note that the caller has already reserved space for count and eof, so xdr->p has already moved past them, only the padding remains. Signed-off-by: Kinglong Mee <kinglongmee@gmail.com> Fixes dc97618ddd (nfsd4: separate splice and readv cases) Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11NFSD: Check acl returned from get_acl/posix_acl_from_modeKinglong Mee
Commit 4ac7249ea5 (nfsd: use get_acl and ->set_acl) don't check the acl returned from get_acl()/posix_acl_from_mode(). Signed-off-by: Kinglong Mee <kinglongmee@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11nfsd: cleanup and rename nfs4_check_openJeff Layton
Rename it to better describe what it does, and have it just return the stateid instead of a __be32 (which is now always nfs_ok). Also, do the search for an existing stateid after the delegation check, to reduce cleanup if the delegation check returns 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>
2014-07-11nfsd: make deny mode enforcement more efficient and close races in itJeff Layton
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>
2014-07-11nfsd: always hold the fi_lock when bumping fi_access refcountsJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11nfsd: clean up reset_union_bmap_denyJeff Layton
Fix the "deny" argument type, and start the loop at 1. The 0 iteration is always a noop. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11nfsd: set stateid access and deny bits in nfs4_get_vfs_fileJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11nfsd: shrink st_access_bmap and st_deny_bmapJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11nfsd: remove nfs4_file_put_fdJeff Layton
...and replace it with a simple swap call. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-11nfsd: refactor nfs4_file_get_access and nfs4_file_put_accessJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-10nfsd: clean up helper __release_lock_stateidTrond Myklebust
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: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-10nfsd: Add locking to the nfs4_file->fi_fds[] arrayTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-10nfsd: Add fine grained protection for the nfs4_file->fi_stateids listTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-10nfsd: reduce some spinlocking in put_client_renewJeff Layton
No need to take the lock unless the count goes to 0. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-10nfsd: close potential race between delegation break and laundromatJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09NFSD: Fix memory leak in encoding denied lockKinglong Mee
Commit 8c7424cff6 (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: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: Convert nfs4_check_open_reclaim() to work with lookup_clientid()Trond Myklebust
lookup_clientid is preferable to find_confirmed_client since it's able to use the cached client in the compound state. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: Always use lookup_clientid() in nfsd4_process_open1Trond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: Convert nfsd4_process_open1() to work with lookup_clientid()Trond Myklebust
...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: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: Allow struct nfsd4_compound_state to cache the nfs4_clientJeff Layton
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: add a nfserrno mapping for -E2BIG to nfserr_fbigJeff Layton
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 <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: properly convert return from commit_metadata to __be32Jeff Layton
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: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: Cleanup - Let nfsd4_lookup_stateid() take a cstate argumentTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: Don't get a session reference without a client referenceTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: clean up nfsd4_release_lockownerJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: NFSv4 lock-owners are not associated to a specific fileTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-09nfsd: Allow lockowners to hold several stateidsJeff Layton
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: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: lock owners are not per open stateidTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: clean up nfsd4_close_open_stateidTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: declare v4.1+ openowners confirmed on creationJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: Cleanup nfs4svc_encode_compoundresTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: nfs4_preprocess_seqid_op should only set *stpp on successTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: add a new /proc/fs/nfsd/max_connections fileJeff Layton
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: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: Ensure that nfsd_create_setattr commits files to stable storageTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08NFSD: Remove iattr parameter from nfsd_symlink()Kinglong Mee
Commit db2e747b1499 (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: Kinglong Mee <kinglongmee@gmail.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: Protect addition to the file_hashtblTrond Myklebust
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: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: fix file access refcount leak when nfsd4_truncate failsChristoph Hellwig
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: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08NFSD: Avoid warning message when compile at i686 archKinglong Mee
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: Kinglong Mee <kinglongmee@gmail.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd4: replace defer_free by svcxdr_tmpallocJ. Bruce Fields
Avoid an extra allocation for the tmpbuf struct itself, and stop ignoring some allocation failures. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd4: remove nfs4_acl_newJ. Bruce Fields
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 <bfields@redhat.com>
2014-07-08nfsd4: define svcxdr_dupstr to share some common codeJ. Bruce Fields
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd4: remove unused defer_free argumentJ. Bruce Fields
28e05dd8457c "knfsd: nfsd4: represent nfsv4 acl with array instead of linked list" removed the last user that wanted a custom free function. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd4: rename cr_linkname->cr_dataJ. Bruce Fields
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: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: let nfsd_symlink assume null-terminated dataJ. Bruce Fields
Currently nfsd_symlink has a weird hack to serve callers who don't null-terminate symlink data: it looks ahead at the next byte to see if it's zero, and copies it to a new buffer to null-terminate if not. That means callers don't have to null-terminate, but they *do* have to ensure that the byte following the end of the data is theirs to read. That's a bit subtle, and the NFSv4 code actually got this wrong. So let's just throw out that code and let callers pass null-terminated strings; we've already fixed them to do that. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: make NFSv2 null terminate symlink dataJ. Bruce Fields
It's simple enough for NFSv2 to null-terminate the symlink data. A bit weird (it depends on knowing that we've already read the following byte, which is either padding or part of the mode), but no worse than the conditional kstrdup it otherwise relies on in nfsd_symlink(). Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-08nfsd: fix rare symlink decoding bugJ. Bruce Fields
An NFS operation that creates a new symlink includes the symlink data, which is xdr-encoded as a length followed by the data plus 0 to 3 bytes of zero-padding as required to reach a 4-byte boundary. The vfs, on the other hand, wants null-terminated data. The simple way to handle this would be by copying the data into a newly allocated buffer with space for the final null. The current nfsd_symlink code tries to be more clever by skipping that step in the (likely) case where the byte following the string is already 0. But that assumes that the byte following the string is ours to look at. In fact, it might be the first byte of a page that we can't read, or of some object that another task might modify. Worse, the NFSv4 code tries to fix the problem by actually writing to that byte. In the NFSv2/v3 cases this actually appears to be safe: - nfs3svc_decode_symlinkargs explicitly null-terminates the data (after first checking its length and copying it to a new page). - NFSv2 limits symlinks to 1k. The buffer holding the rpc request is always at least a page, and the link data (and previous fields) have maximum lengths that prevent the request from reaching the end of a page. In the NFSv4 case the CREATE op is potentially just one part of a long compound so can end up on the end of a page if you're unlucky. The minimal fix here is to copy and null-terminate in the NFSv4 case. The nfsd_symlink() interface here seems too fragile, though. It should really either do the copy itself every time or just require a null-terminated string. Reported-by: Jeff Layton <jlayton@primarydata.com> Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-07nfsd: Fix bad reserving space for encoding rdattr_errorKinglong Mee
Introduced by commit 561f0ed498 (nfsd4: allow large readdirs). Signed-off-by: Kinglong Mee <kinglongmee@gmail.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>