user/sven/linux.git/include/linux/quota.h, branch v5.10.221

quota: Fix slow quotaoff

2023-10-25T09:54:13Z

commit 869b6ea1609f655a43251bf41757aa44e5350a8f upstream. Eric has reported that commit dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") heavily increases runtime of generic/270 xfstest for ext4 in nojournal mode. The reason for this is that ext4 in nojournal mode leaves dquots dirty until the last dqput() and thus the cleanup done in quota_release_workfn() has to write them all. Due to the way quota_release_workfn() is written this results in synchronize_srcu() call for each dirty dquot which makes the dquot cleanup when turning quotas off extremely slow. To be able to avoid synchronize_srcu() for each dirty dquot we need to rework how we track dquots to be cleaned up. Instead of keeping the last dquot reference while it is on releasing_dquots list, we drop it right away and mark the dquot with new DQ_RELEASING_B bit instead. This way we can we can remove dquot from releasing_dquots list when new reference to it is acquired and thus there's no need to call synchronize_srcu() each time we drop dq_list_lock. References: https://lore.kernel.org/all/ZRytn6CxFK2oECUt@debian-BULLSEYE-live-builder-AMD64 Reported-by: Eric Whitney Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") CC: stable@vger.kernel.org Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman

fs/quota: handle overflows of sysctl fs.quota.* and report as unsigned long

2019-11-11T10:06:27Z

Quota statistics counted as 64-bit per-cpu counter. Reading sums per-cpu fractions as signed 64-bit int, filters negative values and then reports lower half as signed 32-bit int. Result may looks like: fs.quota.allocated_dquots = 22327 fs.quota.cache_hits = -489852115 fs.quota.drops = -487288718 fs.quota.free_dquots = 22083 fs.quota.lookups = -486883485 fs.quota.reads = 22327 fs.quota.syncs = 335064 fs.quota.writes = 3088689 Values bigger than 2^31-1 reported as negative. All counters except "allocated_dquots" and "free_dquots" are monotonic, thus they should be reported as is without filtering negative values. Kernel doesn't have generic helper for 64-bit sysctl yet, let's use at least unsigned long. Link: https://lore.kernel.org/r/157337934693.2078.9842146413181153727.stgit@buzz Signed-off-by: Konstantin Khlebnikov Signed-off-by: Jan Kara

fs/quota: Replace XQM_MAXQUOTAS usage with MAXQUOTAS

2018-08-22T16:17:29Z

XQM_MAXQUOTAS and MAXQUOTAS are, it appears, equivalent. Replace all usage of XQM_MAXQUOTAS and remove it along with the unused XQM_*QUOTA definitions. Signed-off-by: Jeremy Cline Signed-off-by: Jan Kara

quota: Kill an unused extern entry form quota.h

2018-03-26T11:11:35Z

Kill an unused extern entry from quota.h which is leftover of below patch. [f32764bd2: quota: Convert quota statistics to generic percpu_counter] Signed-off-by: Ritesh Harjani Signed-off-by: Jan Kara

quota: Add lock annotations to struct members

2017-08-21T12:06:46Z

Add annotation which lock protects which struct members to struct dquot and struct mem_dqinfo. Signed-off-by: Jan Kara

quota: Reduce contention on dq_data_lock

2017-08-17T20:07:59Z

dq_data_lock is currently used to protect all modifications of quota accounting information, consistency of quota accounting on the inode, and dquot pointers from inode. As a result contention on the lock can be pretty heavy. Reduce the contention on the lock by protecting quota accounting information by a new dquot->dq_dqb_lock and consistency of quota accounting with inode usage by inode->i_lock. This change reduces time to create 500000 files on ext4 on ramdisk by 50 different processes in separate directories by 6% when user quota is turned on. When those 50 processes belong to 50 different users, the improvement is about 9%. Signed-off-by: Jan Kara

quota: Allow disabling tracking of dirty dquots in a list

2017-08-17T20:00:45Z

Filesystems that are journalling quotas generally don't need tracking of dirty dquots in a list since forcing a transaction commit flushes all quotas anyway. Allow filesystem to say it doesn't want dquots to be tracked as it reduces contention on the dq_list_lock. Signed-off-by: Jan Kara

quota: Remove dq_wait_unused from dquot

2017-08-17T20:00:40Z

Currently every dquot carries a wait_queue_head_t used only when we are turning quotas off to wait for last users to drop dquot references. Since such rare case is not performance sensitive in any means, just use a global waitqueue for this and save space in struct dquot. Also convert the logic to use wait_event() instead of open-coding it. Signed-off-by: Jan Kara

quota: Convert dqio_mutex to rwsem

2017-08-17T16:52:48Z

Convert dqio_mutex to rwsem and call it dqio_sem. No functional changes yet. Signed-off-by: Jan Kara

quota: add get_inode_usage callback to transfer multi-inode charges

2017-06-22T15:46:48Z

Ext4 ea_inode feature allows storing xattr values in external inodes to be able to store values that are bigger than a block in size. Ext4 also has deduplication support for these type of inodes. With deduplication, the actual storage waste is eliminated but the users of such inodes are still charged full quota for the inodes as if there was no sharing happening in the background. This design requires ext4 to manually charge the users because the inodes are shared. An implication of this is that, if someone calls chown on a file that has such references we need to transfer the quota for the file and xattr inodes. Current dquot_transfer() function implicitly transfers one inode charge. With ea_inode feature, we would like to transfer multiple inode charges. Add get_inode_usage callback which can interrogate the total number of inodes that were charged for a given inode. [ Applied fix from Colin King to make sure the 'ret' variable is initialized on the successful return path. Detected by CoverityScan, CID#1446616 ("Uninitialized scalar variable") --tytso] Signed-off-by: Tahsin Erdogan Signed-off-by: Theodore Ts'o Signed-off-by: Colin Ian King Acked-by: Jan Kara