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| author | Al Viro <viro@zeniv.linux.org.uk> | 2016-08-29 20:56:35 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-12-10 14:25:18 -0500 |
| commit | 77469c3f570e329acb631c5c03780eacdca2a534 (patch) | |
| tree | 56f89cbfd95a55f5d750710d9ca950bf8992fdf1 /fs/9p | |
| parent | 43388b21e72d36204822bcc3119e42abe6ebceef (diff) | |
| download | linux-stable-77469c3f570e329acb631c5c03780eacdca2a534.tar.gz linux-stable-77469c3f570e329acb631c5c03780eacdca2a534.tar.bz2 linux-stable-77469c3f570e329acb631c5c03780eacdca2a534.zip | |
9p: saner ->write_end() on failing copy into non-uptodate page
If we had a short copy into an uptodate page, there's no reason
whatsoever to zero anything; OTOH, if that page had _not_ been
uptodate, we must have been trying to overwrite it completely
and got a short copy. In that case, overwriting the end with
zeroes, marking uptodate and sending to server is just plain
wrong. Just unlock, keep it non-uptodate and return 0.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/9p')
| -rw-r--r-- | fs/9p/vfs_addr.c | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index 6181ad79e1a5..ff8ece89fb99 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -309,18 +309,10 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping, p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); - if (unlikely(copied < len)) { - /* - * zero out the rest of the area - */ - unsigned from = pos & (PAGE_SIZE - 1); - - zero_user(page, from + copied, len - copied); - flush_dcache_page(page); + if (unlikely(copied < len && !PageUptodate(page))) { + copied = 0; + goto out; } - - if (!PageUptodate(page)) - SetPageUptodate(page); /* * No need to use i_size_read() here, the i_size * cannot change under us because we hold the i_mutex. @@ -330,6 +322,7 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping, i_size_write(inode, last_pos); } set_page_dirty(page); +out: unlock_page(page); put_page(page); |