From 7b2404a886f8b91250c31855d287e632123e1746 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 1 Dec 2023 00:22:00 +0000 Subject: [PATCH 1/6] cifs: Fix flushing, invalidation and file size with copy_file_range() Fix a number of issues in the cifs filesystem implementation of the copy_file_range() syscall in cifs_file_copychunk_range(). Firstly, the invalidation of the destination range is handled incorrectly: We shouldn't just invalidate the whole file as dirty data in the file may get lost and we can't just call truncate_inode_pages_range() to invalidate the destination range as that will erase parts of a partial folio at each end whilst invalidating and discarding all the folios in the middle. We need to force all the folios covering the range to be reloaded, but we mustn't lose dirty data in them that's not in the destination range. Further, we shouldn't simply round out the range to PAGE_SIZE at each end as cifs should move to support multipage folios. Secondly, there's an issue whereby a write may have extended the file locally, but not have been written back yet. This can leaves the local idea of the EOF at a later point than the server's EOF. If a copy request is issued, this will fail on the server with STATUS_INVALID_VIEW_SIZE (which gets translated to -EIO locally) if the copy source extends past the server's EOF. Fix this by: (0) Flush the source region (already done). The flush does nothing and the EOF isn't moved if the source region has no dirty data. (1) Move the EOF to the end of the source region if it isn't already at least at this point. If we can't do this, for instance if the server doesn't support it, just flush the entire source file. (2) Find the folio (if present) at each end of the range, flushing it and increasing the region-to-be-invalidated to cover those in their entirety. (3) Fully discard all the folios covering the range as we want them to be reloaded. (4) Then perform the copy. Thirdly, set i_size after doing the copychunk_range operation as this value may be used by various things internally. stat() hides the issue because setting ->time to 0 causes cifs_getatr() to revalidate the attributes. These were causing the generic/075 xfstest to fail. Fixes: 620d8745b35d ("Introduce cifs_copy_file_range()") Cc: stable@vger.kernel.org Signed-off-by: David Howells cc: Paulo Alcantara cc: Shyam Prasad N cc: Rohith Surabattula cc: Matthew Wilcox cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: linux-mm@kvack.org Signed-off-by: David Howells Signed-off-by: Steve French --- fs/smb/client/cifsfs.c | 102 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 99 insertions(+), 3 deletions(-) diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c index ea3a7a668b45..8097a9b3e98c 100644 --- a/fs/smb/client/cifsfs.c +++ b/fs/smb/client/cifsfs.c @@ -1196,6 +1196,72 @@ const struct inode_operations cifs_symlink_inode_ops = { .listxattr = cifs_listxattr, }; +/* + * Advance the EOF marker to after the source range. + */ +static int cifs_precopy_set_eof(struct inode *src_inode, struct cifsInodeInfo *src_cifsi, + struct cifs_tcon *src_tcon, + unsigned int xid, loff_t src_end) +{ + struct cifsFileInfo *writeable_srcfile; + int rc = -EINVAL; + + writeable_srcfile = find_writable_file(src_cifsi, FIND_WR_FSUID_ONLY); + if (writeable_srcfile) { + if (src_tcon->ses->server->ops->set_file_size) + rc = src_tcon->ses->server->ops->set_file_size( + xid, src_tcon, writeable_srcfile, + src_inode->i_size, true /* no need to set sparse */); + else + rc = -ENOSYS; + cifsFileInfo_put(writeable_srcfile); + cifs_dbg(FYI, "SetFSize for copychunk rc = %d\n", rc); + } + + if (rc < 0) + goto set_failed; + + netfs_resize_file(&src_cifsi->netfs, src_end); + fscache_resize_cookie(cifs_inode_cookie(src_inode), src_end); + return 0; + +set_failed: + return filemap_write_and_wait(src_inode->i_mapping); +} + +/* + * Flush out either the folio that overlaps the beginning of a range in which + * pos resides or the folio that overlaps the end of a range unless that folio + * is entirely within the range we're going to invalidate. We extend the flush + * bounds to encompass the folio. + */ +static int cifs_flush_folio(struct inode *inode, loff_t pos, loff_t *_fstart, loff_t *_fend, + bool first) +{ + struct folio *folio; + unsigned long long fpos, fend; + pgoff_t index = pos / PAGE_SIZE; + size_t size; + int rc = 0; + + folio = filemap_get_folio(inode->i_mapping, index); + if (IS_ERR(folio)) + return 0; + + size = folio_size(folio); + fpos = folio_pos(folio); + fend = fpos + size - 1; + *_fstart = min_t(unsigned long long, *_fstart, fpos); + *_fend = max_t(unsigned long long, *_fend, fend); + if ((first && pos == fpos) || (!first && pos == fend)) + goto out; + + rc = filemap_write_and_wait_range(inode->i_mapping, fpos, fend); +out: + folio_put(folio); + return rc; +} + static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, struct file *dst_file, loff_t destoff, loff_t len, unsigned int remap_flags) @@ -1263,10 +1329,12 @@ ssize_t cifs_file_copychunk_range(unsigned int xid, { struct inode *src_inode = file_inode(src_file); struct inode *target_inode = file_inode(dst_file); + struct cifsInodeInfo *src_cifsi = CIFS_I(src_inode); struct cifsFileInfo *smb_file_src; struct cifsFileInfo *smb_file_target; struct cifs_tcon *src_tcon; struct cifs_tcon *target_tcon; + unsigned long long destend, fstart, fend; ssize_t rc; cifs_dbg(FYI, "copychunk range\n"); @@ -1306,13 +1374,41 @@ ssize_t cifs_file_copychunk_range(unsigned int xid, if (rc) goto unlock; - /* should we flush first and last page first */ - truncate_inode_pages(&target_inode->i_data, 0); + /* The server-side copy will fail if the source crosses the EOF marker. + * Advance the EOF marker after the flush above to the end of the range + * if it's short of that. + */ + if (src_cifsi->server_eof < off + len) { + rc = cifs_precopy_set_eof(src_inode, src_cifsi, src_tcon, xid, off + len); + if (rc < 0) + goto unlock; + } + + destend = destoff + len - 1; + + /* Flush the folios at either end of the destination range to prevent + * accidental loss of dirty data outside of the range. + */ + fstart = destoff; + fend = destend; + + rc = cifs_flush_folio(target_inode, destoff, &fstart, &fend, true); + if (rc) + goto unlock; + rc = cifs_flush_folio(target_inode, destend, &fstart, &fend, false); + if (rc) + goto unlock; + + /* Discard all the folios that overlap the destination region. */ + truncate_inode_pages_range(&target_inode->i_data, fstart, fend); rc = file_modified(dst_file); - if (!rc) + if (!rc) { rc = target_tcon->ses->server->ops->copychunk_range(xid, smb_file_src, smb_file_target, off, len, destoff); + if (rc > 0 && destoff + rc > i_size_read(target_inode)) + truncate_setsize(target_inode, destoff + rc); + } file_accessed(src_file); From c54fc3a4f375663f2361a9cbb2955fb4ef912879 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 1 Dec 2023 00:22:01 +0000 Subject: [PATCH 2/6] cifs: Fix flushing, invalidation and file size with FICLONE Fix a number of issues in the cifs filesystem implementation of the FICLONE ioctl in cifs_remap_file_range(). This is analogous to the previously fixed bug in cifs_file_copychunk_range() and can share the helper functions. Firstly, the invalidation of the destination range is handled incorrectly: We shouldn't just invalidate the whole file as dirty data in the file may get lost and we can't just call truncate_inode_pages_range() to invalidate the destination range as that will erase parts of a partial folio at each end whilst invalidating and discarding all the folios in the middle. We need to force all the folios covering the range to be reloaded, but we mustn't lose dirty data in them that's not in the destination range. Further, we shouldn't simply round out the range to PAGE_SIZE at each end as cifs should move to support multipage folios. Secondly, there's an issue whereby a write may have extended the file locally, but not have been written back yet. This can leaves the local idea of the EOF at a later point than the server's EOF. If a clone request is issued, this will fail on the server with STATUS_INVALID_VIEW_SIZE (which gets translated to -EIO locally) if the clone source extends past the server's EOF. Fix this by: (0) Flush the source region (already done). The flush does nothing and the EOF isn't moved if the source region has no dirty data. (1) Move the EOF to the end of the source region if it isn't already at least at this point. If we can't do this, for instance if the server doesn't support it, just flush the entire source file. (2) Find the folio (if present) at each end of the range, flushing it and increasing the region-to-be-invalidated to cover those in their entirety. (3) Fully discard all the folios covering the range as we want them to be reloaded. (4) Then perform the extent duplication. Thirdly, set i_size after doing the duplicate_extents operation as this value may be used by various things internally. stat() hides the issue because setting ->time to 0 causes cifs_getatr() to revalidate the attributes. These were causing the cifs/001 xfstest to fail. Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer") Signed-off-by: David Howells Cc: stable@vger.kernel.org cc: Christoph Hellwig cc: Paulo Alcantara cc: Shyam Prasad N cc: Rohith Surabattula cc: Matthew Wilcox cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: linux-mm@kvack.org Signed-off-by: David Howells Signed-off-by: Steve French --- fs/smb/client/cifsfs.c | 68 +++++++++++++++++++++++++++++++++++------- 1 file changed, 57 insertions(+), 11 deletions(-) diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c index 8097a9b3e98c..c5fc0a35bb19 100644 --- a/fs/smb/client/cifsfs.c +++ b/fs/smb/client/cifsfs.c @@ -1268,9 +1268,12 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, { struct inode *src_inode = file_inode(src_file); struct inode *target_inode = file_inode(dst_file); + struct cifsInodeInfo *src_cifsi = CIFS_I(src_inode); + struct cifsInodeInfo *target_cifsi = CIFS_I(target_inode); struct cifsFileInfo *smb_file_src = src_file->private_data; - struct cifsFileInfo *smb_file_target; - struct cifs_tcon *target_tcon; + struct cifsFileInfo *smb_file_target = dst_file->private_data; + struct cifs_tcon *target_tcon, *src_tcon; + unsigned long long destend, fstart, fend, new_size; unsigned int xid; int rc; @@ -1281,13 +1284,13 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, xid = get_xid(); - if (!src_file->private_data || !dst_file->private_data) { + if (!smb_file_src || !smb_file_target) { rc = -EBADF; cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n"); goto out; } - smb_file_target = dst_file->private_data; + src_tcon = tlink_tcon(smb_file_src->tlink); target_tcon = tlink_tcon(smb_file_target->tlink); /* @@ -1300,20 +1303,63 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, if (len == 0) len = src_inode->i_size - off; - cifs_dbg(FYI, "about to flush pages\n"); - /* should we flush first and last page first */ - truncate_inode_pages_range(&target_inode->i_data, destoff, - PAGE_ALIGN(destoff + len)-1); + cifs_dbg(FYI, "clone range\n"); - if (target_tcon->ses->server->ops->duplicate_extents) + /* Flush the source buffer */ + rc = filemap_write_and_wait_range(src_inode->i_mapping, off, + off + len - 1); + if (rc) + goto unlock; + + /* The server-side copy will fail if the source crosses the EOF marker. + * Advance the EOF marker after the flush above to the end of the range + * if it's short of that. + */ + if (src_cifsi->netfs.remote_i_size < off + len) { + rc = cifs_precopy_set_eof(src_inode, src_cifsi, src_tcon, xid, off + len); + if (rc < 0) + goto unlock; + } + + new_size = destoff + len; + destend = destoff + len - 1; + + /* Flush the folios at either end of the destination range to prevent + * accidental loss of dirty data outside of the range. + */ + fstart = destoff; + fend = destend; + + rc = cifs_flush_folio(target_inode, destoff, &fstart, &fend, true); + if (rc) + goto unlock; + rc = cifs_flush_folio(target_inode, destend, &fstart, &fend, false); + if (rc) + goto unlock; + + /* Discard all the folios that overlap the destination region. */ + cifs_dbg(FYI, "about to discard pages %llx-%llx\n", fstart, fend); + truncate_inode_pages_range(&target_inode->i_data, fstart, fend); + + fscache_invalidate(cifs_inode_cookie(target_inode), NULL, + i_size_read(target_inode), 0); + + rc = -EOPNOTSUPP; + if (target_tcon->ses->server->ops->duplicate_extents) { rc = target_tcon->ses->server->ops->duplicate_extents(xid, smb_file_src, smb_file_target, off, len, destoff); - else - rc = -EOPNOTSUPP; + if (rc == 0 && new_size > i_size_read(target_inode)) { + truncate_setsize(target_inode, new_size); + netfs_resize_file(&target_cifsi->netfs, new_size); + fscache_resize_cookie(cifs_inode_cookie(target_inode), + new_size); + } + } /* force revalidate of size and timestamps of target file now that target is updated on the server */ CIFS_I(target_inode)->time = 0; +unlock: /* although unlocking in the reverse order from locking is not strictly necessary here it is a little cleaner to be consistent */ unlock_two_nondirectories(src_inode, target_inode); From 92414333eb375ed64f4ae92d34d579e826936480 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Tue, 5 Dec 2023 21:49:29 -0300 Subject: [PATCH 3/6] smb: client: fix potential NULL deref in parse_dfs_referrals() If server returned no data for FSCTL_DFS_GET_REFERRALS, @dfs_rsp will remain NULL and then parse_dfs_referrals() will dereference it. Fix this by returning -EIO when no output data is returned. Besides, we can't fix it in SMB2_ioctl() as some FSCTLs are allowed to return no data as per MS-SMB2 2.2.32. Fixes: 9d49640a21bf ("CIFS: implement get_dfs_refer for SMB2+") Cc: stable@vger.kernel.org Reported-by: Robert Morris Signed-off-by: Paulo Alcantara (SUSE) Signed-off-by: Steve French --- fs/smb/client/smb2ops.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index 45931115f475..fcfb6566b899 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -2836,6 +2836,8 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, usleep_range(512, 2048); } while (++retry_count < 5); + if (!rc && !dfs_rsp) + rc = -EIO; if (rc) { if (!is_retryable_error(rc) && rc != -ENOENT && rc != -EOPNOTSUPP) cifs_tcon_dbg(VFS, "%s: ioctl error: rc=%d\n", __func__, rc); From 691a41d8da4b34fe72f09393505f55f28a8f34ec Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 4 Dec 2023 14:01:59 +0000 Subject: [PATCH 4/6] cifs: Fix non-availability of dedup breaking generic/304 Deduplication isn't supported on cifs, but cifs doesn't reject it, instead treating it as extent duplication/cloning. This can cause generic/304 to go silly and run for hours on end. Fix cifs to indicate EOPNOTSUPP if REMAP_FILE_DEDUP is set in ->remap_file_range(). Note that it's unclear whether or not commit b073a08016a1 is meant to cause cifs to return an error if REMAP_FILE_DEDUP. Fixes: b073a08016a1 ("cifs: fix that return -EINVAL when do dedupe operation") Cc: stable@vger.kernel.org Suggested-by: Dave Chinner cc: Xiaoli Feng cc: Shyam Prasad N cc: Rohith Surabattula cc: Jeff Layton cc: Darrick Wong cc: fstests@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/3876191.1701555260@warthog.procyon.org.uk/ Signed-off-by: David Howells Signed-off-by: Steve French --- fs/smb/client/cifsfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c index c5fc0a35bb19..2131638f26d0 100644 --- a/fs/smb/client/cifsfs.c +++ b/fs/smb/client/cifsfs.c @@ -1277,7 +1277,9 @@ static loff_t cifs_remap_file_range(struct file *src_file, loff_t off, unsigned int xid; int rc; - if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY)) + if (remap_flags & REMAP_FILE_DEDUP) + return -EOPNOTSUPP; + if (remap_flags & ~REMAP_FILE_ADVISORY) return -EINVAL; cifs_dbg(FYI, "clone range\n"); From 823342524868168bf681f135d01b4ae10f5863ec Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Wed, 6 Dec 2023 16:37:37 +0000 Subject: [PATCH 5/6] Revert "cifs: reconnect work should have reference on server struct" This reverts commit 19a4b9d6c372cab6a3b2c9a061a236136fe95274. This earlier commit was making an assumption that each mod_delayed_work called for the reconnect work would result in smb2_reconnect_server being called twice. This assumption turns out to be untrue. So reverting this change for now. I will submit a follow-up patch to fix the actual problem in a different way. Signed-off-by: Shyam Prasad N Signed-off-by: Steve French --- fs/smb/client/connect.c | 27 ++++++--------------------- fs/smb/client/smb2pdu.c | 23 ++++++++++------------- 2 files changed, 16 insertions(+), 34 deletions(-) diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index f896f60c924b..e07975173cf4 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -402,13 +402,7 @@ static int __cifs_reconnect(struct TCP_Server_Info *server, spin_unlock(&server->srv_lock); cifs_swn_reset_server_dstaddr(server); cifs_server_unlock(server); - - /* increase ref count which reconnect work will drop */ - spin_lock(&cifs_tcp_ses_lock); - server->srv_count++; - spin_unlock(&cifs_tcp_ses_lock); - if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0)) - cifs_put_tcp_session(server, false); + mod_delayed_work(cifsiod_wq, &server->reconnect, 0); } } while (server->tcpStatus == CifsNeedReconnect); @@ -538,13 +532,7 @@ static int reconnect_dfs_server(struct TCP_Server_Info *server) spin_unlock(&server->srv_lock); cifs_swn_reset_server_dstaddr(server); cifs_server_unlock(server); - - /* increase ref count which reconnect work will drop */ - spin_lock(&cifs_tcp_ses_lock); - server->srv_count++; - spin_unlock(&cifs_tcp_ses_lock); - if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0)) - cifs_put_tcp_session(server, false); + mod_delayed_work(cifsiod_wq, &server->reconnect, 0); } while (server->tcpStatus == CifsNeedReconnect); mutex_lock(&server->refpath_lock); @@ -1626,19 +1614,16 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect) cancel_delayed_work_sync(&server->echo); - if (from_reconnect) { + if (from_reconnect) /* * Avoid deadlock here: reconnect work calls * cifs_put_tcp_session() at its end. Need to be sure * that reconnect work does nothing with server pointer after * that step. */ - if (cancel_delayed_work(&server->reconnect)) - cifs_put_tcp_session(server, from_reconnect); - } else { - if (cancel_delayed_work_sync(&server->reconnect)) - cifs_put_tcp_session(server, from_reconnect); - } + cancel_delayed_work(&server->reconnect); + else + cancel_delayed_work_sync(&server->reconnect); spin_lock(&server->srv_lock); server->tcpStatus = CifsExiting; diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index 395e1230ddbc..9d7289f8d87b 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -3952,6 +3952,12 @@ void smb2_reconnect_server(struct work_struct *work) } spin_unlock(&ses->chan_lock); } + /* + * Get the reference to server struct to be sure that the last call of + * cifs_put_tcon() in the loop below won't release the server pointer. + */ + if (tcon_exist || ses_exist) + server->srv_count++; spin_unlock(&cifs_tcp_ses_lock); @@ -3999,17 +4005,13 @@ void smb2_reconnect_server(struct work_struct *work) done: cifs_dbg(FYI, "Reconnecting tcons and channels finished\n"); - if (resched) { + if (resched) queue_delayed_work(cifsiod_wq, &server->reconnect, 2 * HZ); - mutex_unlock(&pserver->reconnect_mutex); - - /* no need to put tcp session as we're retrying */ - return; - } mutex_unlock(&pserver->reconnect_mutex); /* now we can safely release srv struct */ - cifs_put_tcp_session(server, true); + if (tcon_exist || ses_exist) + cifs_put_tcp_session(server, 1); } int @@ -4029,12 +4031,7 @@ SMB2_echo(struct TCP_Server_Info *server) server->ops->need_neg(server)) { spin_unlock(&server->srv_lock); /* No need to send echo on newly established connections */ - spin_lock(&cifs_tcp_ses_lock); - server->srv_count++; - spin_unlock(&cifs_tcp_ses_lock); - if (mod_delayed_work(cifsiod_wq, &server->reconnect, 0)) - cifs_put_tcp_session(server, false); - + mod_delayed_work(cifsiod_wq, &server->reconnect, 0); return rc; } spin_unlock(&server->srv_lock); From 04909192ada3285070f8ced0af7f07735478b364 Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Wed, 6 Dec 2023 16:37:38 +0000 Subject: [PATCH 6/6] cifs: reconnect worker should take reference on server struct unconditionally Reconnect worker currently assumes that the server struct is alive and only takes reference on the server if it needs to call smb2_reconnect. With the new ability to disable channels based on whether the server has multichannel disabled, this becomes a problem when we need to disable established channels. While disabling the channels and deallocating the server, there could be reconnect work that could not be cancelled (because it started). This change forces the reconnect worker to unconditionally take a reference on the server when it runs. Also, this change now allows smb2_reconnect to know if it was called by the reconnect worker. Based on this, the cifs_put_tcp_session can decide whether it can cancel the reconnect work synchronously or not. Signed-off-by: Shyam Prasad N Signed-off-by: Steve French --- fs/smb/client/connect.c | 8 ++++---- fs/smb/client/smb2pdu.c | 29 +++++++++++++++-------------- 2 files changed, 19 insertions(+), 18 deletions(-) diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index e07975173cf4..9dc6dc2754c2 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -1608,10 +1608,6 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect) list_del_init(&server->tcp_ses_list); spin_unlock(&cifs_tcp_ses_lock); - /* For secondary channels, we pick up ref-count on the primary server */ - if (SERVER_IS_CHAN(server)) - cifs_put_tcp_session(server->primary_server, from_reconnect); - cancel_delayed_work_sync(&server->echo); if (from_reconnect) @@ -1625,6 +1621,10 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect) else cancel_delayed_work_sync(&server->reconnect); + /* For secondary channels, we pick up ref-count on the primary server */ + if (SERVER_IS_CHAN(server)) + cifs_put_tcp_session(server->primary_server, from_reconnect); + spin_lock(&server->srv_lock); server->tcpStatus = CifsExiting; spin_unlock(&server->srv_lock); diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index 9d7289f8d87b..20634fc6d4f0 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -158,7 +158,7 @@ out: static int smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, - struct TCP_Server_Info *server) + struct TCP_Server_Info *server, bool from_reconnect) { int rc = 0; struct nls_table *nls_codepage = NULL; @@ -331,7 +331,7 @@ again: * as cifs_put_tcp_session takes a higher lock * i.e. cifs_tcp_ses_lock */ - cifs_put_tcp_session(server, 1); + cifs_put_tcp_session(server, from_reconnect); server->terminate = true; cifs_signal_cifsd_for_reconnect(server, false); @@ -499,7 +499,7 @@ static int smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon, { int rc; - rc = smb2_reconnect(smb2_command, tcon, server); + rc = smb2_reconnect(smb2_command, tcon, server, false); if (rc) return rc; @@ -3895,6 +3895,15 @@ void smb2_reconnect_server(struct work_struct *work) int rc; bool resched = false; + /* first check if ref count has reached 0, if not inc ref count */ + spin_lock(&cifs_tcp_ses_lock); + if (!server->srv_count) { + spin_unlock(&cifs_tcp_ses_lock); + return; + } + server->srv_count++; + spin_unlock(&cifs_tcp_ses_lock); + /* If server is a channel, select the primary channel */ pserver = SERVER_IS_CHAN(server) ? server->primary_server : server; @@ -3952,17 +3961,10 @@ void smb2_reconnect_server(struct work_struct *work) } spin_unlock(&ses->chan_lock); } - /* - * Get the reference to server struct to be sure that the last call of - * cifs_put_tcon() in the loop below won't release the server pointer. - */ - if (tcon_exist || ses_exist) - server->srv_count++; - spin_unlock(&cifs_tcp_ses_lock); list_for_each_entry_safe(tcon, tcon2, &tmp_list, rlist) { - rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server); + rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server, true); if (!rc) cifs_reopen_persistent_handles(tcon); else @@ -3995,7 +3997,7 @@ void smb2_reconnect_server(struct work_struct *work) /* now reconnect sessions for necessary channels */ list_for_each_entry_safe(ses, ses2, &tmp_ses_list, rlist) { tcon->ses = ses; - rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server); + rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server, true); if (rc) resched = true; list_del_init(&ses->rlist); @@ -4010,8 +4012,7 @@ done: mutex_unlock(&pserver->reconnect_mutex); /* now we can safely release srv struct */ - if (tcon_exist || ses_exist) - cifs_put_tcp_session(server, 1); + cifs_put_tcp_session(server, true); } int