- 12 Apr, 2015 40 commits
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Al Viro authored
it's almost always equal to current_fsuid(), but there's an exception - if the first writeback fid is opened by non-root *and* that happens before root has done any lookups in /, we end up doing attach for root. The current code leaves the resulting FID owned by root from the server POV and by non-root from the client one. Unfortunately, it means that e.g. massive dcache eviction will leave that user buggered - they'll end up redoing walks from / *and* picking that FID every time. As soon as they try to create something, the things will get nasty. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
do it in ->direct_IO()... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
... and make it loop Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
just handle it in ->direct_IO() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Don't mess with kmap() - just use ITER_BVEC. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
... and make it loop until it's done Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
... and have get_user_pages_fast() mapping fewer pages than requested to generate a short read/write. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
... instead of open-coding the call of ->read() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
it's not calling ->write() directly anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
We check if ->ki_pos is positive. However, by that point we have already done rw_verify_area(), which would have rejected such unless the file had been one of /dev/mem, /dev/kmem and /proc/kcore. All of which do not have vectored rw methods, so we would've bailed out even earlier. This check had been introduced before rw_verify_area() had been added there - in fact, it was a subset of checks done on sync paths by rw_verify_area() (back then the /dev/mem exception didn't exist at all). The rest of checks (mandatory locking, etc.) hadn't been added until later. Unfortunately, by the time the call of rw_verify_area() got added, the /dev/mem exception had already appeared, so it wasn't obvious that the older explicit check downstream had become dead code. It *is* a dead code, though, since the few files for which the exception applies do not have ->aio_{read,write}() or ->{read,write}_iter() and for them we won't reach that check anyway. What's more, even if we ever introduce vectored methods for /dev/mem and friends, they'll have to cope with negative positions anyway, since readv(2) and writev(2) are using the same checks as read(2) and write(2) - i.e. rw_verify_area(). Let's bury it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Way, way back kiocb used to be picked from arrays, so ioctx_alloc() checked for multiplication overflow when calculating the size of such array. By the time fs/aio.c went into the tree (in 2002) they were already allocated one-by-one by kmem_cache_alloc(), so that check had already become pointless. Let's bury it... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
it's actually shorter that way *and* later we'll want iocb in scope of generic_write_check() caller. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
unfortunately, allowing an arbitrary 16bit value means a possibility of overflow in the calculation of total number of pages in bio_map_user_iov() - we rely on there being no more than PAGE_SIZE members of sum in the first loop there. If that sum wraps around, we end up allocating too small array of pointers to pages and it's easy to overflow it in the second loop. X-Coverup: TINC (and there's no lumber cartel either) Cc: stable@vger.kernel.org # way, way back Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
... and don't skip access_ok() validation. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
identical to import_single_range() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
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Al Viro authored
We don't need req in either of those. We don't need nr_segs in caller. We don't really need len in caller either - iov_iter_count(&iter) will do. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
the only non-trivial detail is that we do it before rw_verify_area(), so we'd better cap the length ourselves in aio_setup_single_rw() case (for vectored case rw_copy_check_uvector() will do that for us). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
get it closer to matching {compat_,}rw_copy_check_uvector(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
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Andrew Elble authored
We have observed a BUG() crash in fs/attr.c:notify_change(). The crash occurs during an rsync into a filesystem that is exported via NFS. 1.) fs/attr.c:notify_change() modifies the caller's version of attr. 2.) 6de0ec00 ("VFS: make notify_change pass ATTR_KILL_S*ID to setattr operations") introduced a BUG() restriction such that "no function will ever call notify_change() with both ATTR_MODE and ATTR_KILL_S*ID set". Under some circumstances though, it will have assisted in setting the caller's version of attr to this very combination. 3.) 27ac0ffe ("locks: break delegations on any attribute modification") introduced code to handle breaking delegations. This can result in notify_change() being re-called. attr _must_ be explicitly reset to avoid triggering the BUG() established in #2. 4.) The path that that triggers this is via fs/open.c:chmod_common(). The combination of attr flags set here and in the first call to notify_change() along with a later failed break_deleg_wait() results in notify_change() being called again via retry_deleg without resetting attr. Solution is to move retry_deleg in chmod_common() a bit further up to ensure attr is completely reset. There are other places where this seemingly could occur, such as fs/utimes.c:utimes_common(), but the attr flags are not initially set in such a way to trigger this. Fixes: 27ac0ffe ("locks: break delegations on any attribute modification") Reported-by: Eric Meddaugh <etmsys@rit.edu> Tested-by: Eric Meddaugh <etmsys@rit.edu> Signed-off-by: Andrew Elble <aweits@rit.edu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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J. Bruce Fields authored
On a distributed filesystem it's possible for lookup to discover that a directory it just found is already cached elsewhere in the directory heirarchy. The dcache won't let us keep the directory in both places, so we have to move the dentry to the new location from the place we previously had it cached. If the parent has changed, then this requires all the same locks as we'd need to do a cross-directory rename. But we're already in lookup holding one parent's i_mutex, so it's too late to acquire those locks in the right order. The (unreliable) solution in __d_unalias is to trylock() the required locks and return -EBUSY if it fails. I see no particular reason for returning -EBUSY, and -ESTALE is already the result of some other lookup races on NFS. I think -ESTALE is the more helpful error return. It also allows us to take advantage of the logic Jeff Layton added in c6a94284 "vfs: fix renameat to retry on ESTALE errors" and ancestors, which hopefully resolves some of these errors before they're returned to userspace. I can reproduce these cases using NFS with: ssh root@$client ' mount -olookupcache=pos '$server':'$export' /mnt/ mkdir /mnt/TO mkdir /mnt/DIR touch /mnt/DIR/test.txt while true; do strace -e open cat /mnt/DIR/test.txt 2>&1 | grep EBUSY done ' ssh root@$server ' while true; do mv $export/DIR $export/TO/DIR mv $export/TO/DIR $export/DIR done ' It also helps to add some other concurrent use of the directory on the client (e.g., "ls /mnt/TO"). And you can replace the server-side mv's by client-side mv's that are repeatedly killed. (If the client is interrupted while waiting for the RENAME response then it's left with a dentry that has to go under one parent or the other, but it doesn't yet know which.) Acked-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Anton Altaparmakov authored
Signed-off-by: Anton Altaparmakov <anton@tuxera.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Anton Altaparmakov authored
simillar to iov_iter_fault_in_readable() but differs in that it is not limited to faulting in the first iovec and instead faults in "bytes" bytes iterating over the iovecs as necessary. Also, instead of only faulting in the first and last page of the range, all pages are faulted in. This function is needed by NTFS when it does multi page file writes. Signed-off-by: Anton Altaparmakov <anton@tuxera.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
For one thing, LOOKUP_DIRECTORY will be dealt with in do_last(). For another, name can be an empty string, but not NULL - no callers pass that and it would oops immediately if they would. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro authored
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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