From 1e249cb5b7fc09ff216aa5a12f6c302e434e88f9 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 12 Jan 2021 11:02:43 -0800 Subject: [PATCH 1/2] fs: fix lazytime expiration handling in __writeback_single_inode() When lazytime is enabled and an inode is being written due to its in-memory updated timestamps having expired, either due to a sync() or syncfs() system call or due to dirtytime_expire_interval having elapsed, the VFS needs to inform the filesystem so that the filesystem can copy the inode's timestamps out to the on-disk data structures. This is done by __writeback_single_inode() calling mark_inode_dirty_sync(), which then calls ->dirty_inode(I_DIRTY_SYNC). However, this occurs after __writeback_single_inode() has already cleared the dirty flags from ->i_state. This causes two bugs: - mark_inode_dirty_sync() redirties the inode, causing it to remain dirty. This wastefully causes the inode to be written twice. But more importantly, it breaks cases where sync_filesystem() is expected to clean dirty inodes. This includes the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl (as reported at https://lore.kernel.org/r/20200306004555.GB225345@gmail.com), as well as possibly filesystem freezing (freeze_super()). - Since ->i_state doesn't contain I_DIRTY_TIME when ->dirty_inode() is called from __writeback_single_inode() for lazytime expiration, xfs_fs_dirty_inode() ignores the notification. (XFS only cares about lazytime expirations, and it assumes that i_state will contain I_DIRTY_TIME during those.) Therefore, lazy timestamps aren't persisted by sync(), syncfs(), or dirtytime_expire_interval on XFS. Fix this by moving the call to mark_inode_dirty_sync() to earlier in __writeback_single_inode(), before the dirty flags are cleared from i_state. This makes filesystems be properly notified of the timestamp expiration, and it avoids incorrectly redirtying the inode. This fixes xfstest generic/580 (which tests FS_IOC_REMOVE_ENCRYPTION_KEY) when run on ext4 or f2fs with lazytime enabled. It also fixes the new lazytime xfstest I've proposed, which reproduces the above-mentioned XFS bug (https://lore.kernel.org/r/20210105005818.92978-1-ebiggers@kernel.org). Alternatively, we could call ->dirty_inode(I_DIRTY_SYNC) directly. But due to the introduction of I_SYNC_QUEUED, mark_inode_dirty_sync() is the right thing to do because mark_inode_dirty_sync() now knows not to move the inode to a writeback list if it is currently queued for sync. Fixes: 0ae45f63d4ef ("vfs: add support for a lazytime mount option") Cc: stable@vger.kernel.org Depends-on: 5afced3bf281 ("writeback: Avoid skipping inode writeback") Link: https://lore.kernel.org/r/20210112190253.64307-2-ebiggers@kernel.org Suggested-by: Jan Kara Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Eric Biggers Signed-off-by: Jan Kara --- fs/fs-writeback.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index acfb55834af2..c41cb887eb7d 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1473,22 +1473,26 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) ret = err; } + /* + * If the inode has dirty timestamps and we need to write them, call + * mark_inode_dirty_sync() to notify the filesystem about it and to + * change I_DIRTY_TIME into I_DIRTY_SYNC. + */ + if ((inode->i_state & I_DIRTY_TIME) && + (wbc->sync_mode == WB_SYNC_ALL || wbc->for_sync || + time_after(jiffies, inode->dirtied_time_when + + dirtytime_expire_interval * HZ))) { + trace_writeback_lazytime(inode); + mark_inode_dirty_sync(inode); + } + /* * Some filesystems may redirty the inode during the writeback * due to delalloc, clear dirty metadata flags right before * write_inode() */ spin_lock(&inode->i_lock); - dirty = inode->i_state & I_DIRTY; - if ((inode->i_state & I_DIRTY_TIME) && - ((dirty & I_DIRTY_INODE) || - wbc->sync_mode == WB_SYNC_ALL || wbc->for_sync || - time_after(jiffies, inode->dirtied_time_when + - dirtytime_expire_interval * HZ))) { - dirty |= I_DIRTY_TIME; - trace_writeback_lazytime(inode); - } inode->i_state &= ~dirty; /* @@ -1509,8 +1513,6 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) spin_unlock(&inode->i_lock); - if (dirty & I_DIRTY_TIME) - mark_inode_dirty_sync(inode); /* Don't write the inode if only I_DIRTY_PAGES was set */ if (dirty & ~I_DIRTY_PAGES) { int err = write_inode(inode, wbc); From 5cdc4a6950a883594e9640b1decb3fcf6222a594 Mon Sep 17 00:00:00 2001 From: lianzhi chang Date: Thu, 14 Jan 2021 15:57:41 +0800 Subject: [PATCH 2/2] udf: fix the problem that the disc content is not displayed When the capacity of the disc is too large (assuming the 4.7G specification), the disc (UDF file system) will be burned multiple times in the windows (Multisession Usage). When the remaining capacity of the CD is less than 300M (estimated value, for reference only), open the CD in the Linux system, the content of the CD is displayed as blank (the kernel will say "No VRS found"). Windows can display the contents of the CD normally. Through analysis, in the "fs/udf/super.c": udf_check_vsd function, the actual value of VSD_MAX_SECTOR_OFFSET may be much larger than 0x800000. According to the current code logic, it is found that the type of sbi->s_session is "__s32", when the remaining capacity of the disc is less than 300M (take a set of test values: sector=3154903040, sbi->s_session=1540464, sb->s_blocksize_bits=11 ), the calculation result of "sbi->s_session << sb->s_blocksize_bits" will overflow. Therefore, it is necessary to convert the type of s_session to "loff_t" (when udf_check_vsd starts, assign a value to _sector, which is also converted in this way), so that the result will not overflow, and then the content of the disc can be displayed normally. Link: https://lore.kernel.org/r/20210114075741.30448-1-changlianzhi@uniontech.com Signed-off-by: lianzhi chang Signed-off-by: Jan Kara --- fs/udf/super.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/udf/super.c b/fs/udf/super.c index 5bef3a68395d..d0df217f4712 100644 --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -705,6 +705,7 @@ static int udf_check_vsd(struct super_block *sb) struct buffer_head *bh = NULL; int nsr = 0; struct udf_sb_info *sbi; + loff_t session_offset; sbi = UDF_SB(sb); if (sb->s_blocksize < sizeof(struct volStructDesc)) @@ -712,7 +713,8 @@ static int udf_check_vsd(struct super_block *sb) else sectorsize = sb->s_blocksize; - sector += (((loff_t)sbi->s_session) << sb->s_blocksize_bits); + session_offset = (loff_t)sbi->s_session << sb->s_blocksize_bits; + sector += session_offset; udf_debug("Starting at sector %u (%lu byte sectors)\n", (unsigned int)(sector >> sb->s_blocksize_bits), @@ -757,8 +759,7 @@ static int udf_check_vsd(struct super_block *sb) if (nsr > 0) return 1; - else if (!bh && sector - (sbi->s_session << sb->s_blocksize_bits) == - VSD_FIRST_SECTOR_OFFSET) + else if (!bh && sector - session_offset == VSD_FIRST_SECTOR_OFFSET) return -1; else return 0;